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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICESPublic Health Service

Xenotransplantation Guidelines Louisa E. Chapman

ICAAC/IDSA Meeting

Geographic Information SystemInfrastructure

Allen W. Hightower

APHA Meeting Martin S. Favero

Southeast Asia IntercountryConsultative Meeting

Samlee Plianbangchang

Hemolytic Uremic Syndrome Mary Beers

Helicobacter hepaticus Jerry M. Rice

HUS in Australia Paul N. Goldwater

Antibiotic Treatment and HUS Abdulaziz A. A. Bin Saeed

HUS Outbreak Sami Al-Qarawi

Epidemic Cholera in the New World Robert V. Tauxe

North American BunyamweraSerogroup Viruses

Charles H. Calisher

Lymphocytic ChoriomeningitisVirus

Leslie L. Barton

Ascension of Wildlife Rabies Charles E. Rupprecht

Tuberculosis in Children Ejaz A. Khan

Data Management Issues Stanley M. Martin

Emerging Infectious Diseases

Vol. 1, No. 4, October–December 1995

EditorsEditorJoseph E. McDade, Ph.D.National Center for Infectious DiseasesCenters for Disease Control and Prevention (CDC)Atlanta, Georgia, USA

Perspectives EditorStephen S. Morse, Ph.D.The Rockefeller UniversityNew York, New York, USA

Synopses EditorPhillip J. Baker, Ph.D.Division of Microbiology and Infectious DiseasesNational Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)Bethesda, Maryland, USA

Dispatches EditorStephen Ostroff, M.D.National Center for Infectious DiseasesCenters for Disease Control and Prevention (CDC)Atlanta, Georgia, USA

Managing EditorPolyxeni Potter, M.A.National Center for Infectious DiseasesCenters for Disease Control and Prevention (CDC)Atlanta, Georgia, USA

Emerging Infectious DiseasesEmerging Infectious Diseases is published four times a year by the National Center for Infectious Diseases,Centers for Disease Control and Prevention (CDC), 1600 Clifton Road., Mailstop C-12, Atlanta, GA 30333,USA. Telephone 404-639-3967, fax 404-639-3039, e-mail [email protected] opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of CDCor the institutions with which the authors are affiliated.All material published in Emerging Infectious Diseases is in the public domain and may be used and reprintedwithout special permission; proper citation, however, is appreciated.Use of trade names is for identification only and does not imply endorsement by the Public Health Service or bythe U.S. Department of Health and Human Services.

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Richard A. Goodman, M.D., M.P.H.Editor, MMWRCenters for Disease Control and Prevention (CDC)Atlanta, Georgia, USA

William Hueston, D.V.M., Ph.DActing Leader, Center for Animal Health MonitoringCenters for Epidemiology and Animal HealthVeterinary Services, Animal and Plant Health Inspection ServiceU.S. Department of AgricultureFort Collins, Colorado, USA

James LeDuc, Ph.D.Advisor for Arboviral DiseasesDivision of Communicable DiseasesWorld Health OrganizationGeneva, Switzerland

Joseph Losos, M.D.Director GeneralLaboratory Center for Disease ControlOntario, Canada

Gerald L. Mandell, M.D.Liaison to Infectious Diseases Society of AmericaUniversity of Virginia Medical CenterCharlottesville, Virginia, USA

Philip P. Mortimer, M.D.Director, Virus Reference DivisionCentral Public Health LaboratoryLondon, United Kingdom

Robert Shope, M.D.Director, Yale Arbovirus Research UnitYale University School of MedicineNew Haven, Connecticut, USA

Bonnie Smoak, M.D.Chief, Dept of EpidemiologyDivision of Preventive MedicineWalter Reed Army Institute of ResearchWashington, D.C., USA

Robert Swanepoel, B.V.Sc., Ph.D.Head, Special Pathogens UnitNational Institute for VirologySandrinham 2131, South Africa

Roberto Tapia, M.D.Director General de EpidemiologíaDirección General de EpidemiologíaSecretaría de SaludMéxico

Editorial and Computer SupportEmerging Infectious Diseases receives editorialand computer support from the Office of Planningand Health Communication, National Center forInfectious Diseases.

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Emerging Infectious Diseases

Instructions to Authors Editorial Material: Manuscripts should be prepared

according to the “Uniform Requirements for ManuscriptsSubmitted to Biomedical Journals” (JAMA 1993:269[17]:2282-6).

Begin each of the following sections on a new page andin this order: title page, abstract, text, acknowledgments,references, each table, figure legends, and figures. On thetitle page, give complete information about each author(full names and highest degree). Give current mailingaddress for correspondence (include fax number ande-mail address). Follow Uniform Requirements style forreferences. Consult List of Journals Indexed in IndexMedicus for accepted journal abbreviations. Tables andfigures should be numbered separately (each beginningwith 1) in the order of mention in the text. Double-spaceeverything, including the title page, abstract, references,tables, and figure legends. Italicize scientific names oforganisms from species name all the way up, except forvernacular names (viruses that have not really beenspeciated, such as coxsackievirus and hepatitis B; bac-terial organisms, such as pseudomonads, salmonellae,and brucellae).

Perspectives: Contributions to the Perspectives sec-tion should address factors known to influence the emer-gence of infectious diseases, including microbial adaptionand change; human demographics and behavior; tech-nology and industry; economic development and landuse; international travel and commerce; and the break-down of public health measures. Articles should be ap-proximately 3,500 words and should include references,not to exceed 40. The section should begin with anintroduction outlining the relationship of the issues dis-cussed in the paper to the emergence of infectious dis-eases. Use of additional subheadings in the main body ofthe text is recommended. If detailed methods are in-cluded, a separate section on experimental proceduresshould immediately follow the body of the text. Photo-graphs and illustrations are optional. Provide a shortabstract (150 words) and a brief biographical sketch.

Synopses: Submit concise reviews of infectious dis-eases or closely related topics. Preference will be given toreviews of new and emerging diseases; however, timely

updates of other diseases or topics are also welcome.Synopses should be approximately 3,500 words andshould include references, not to exceed 40. The sectionshould begin with an introduction outlining the relation-ship of the issues discussed in the paper to the emergenceof infectious diseases. Use of additional subheadings inthe main body of the text is recommended. If detailedmethods are included, a separate section on experimentalprocedures should immediately follow the body of thetext. Photographs and illustrations are optional. Providea short abstract (150 words) and a brief biographicalsketch.

Dispatches: Provide brief updates on trends in infec-tious diseases or infectious disease research. Dispatches(1,000 to 1,500 words of text) should not be divided intosections. Dispatches should begin with a brief introduc-tory statement about the relationship of the topic to theemergence of infectious diseases. Provide references, notto exceed 10, and figures or illustrations, not to exceedtwo.

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Editorial Policy and Call for ArticlesThe goals of Emerging Infectious Diseases (EID) are to promote the recognition of new and reemerging infectious

diseases and to improve the understanding of factors involved in disease emergence, prevention, and elimination. EIDhas an international scope and is intended for professionals in infectious diseases and related sciences. We welcomecontributions from infectious disease specialists in academia, industry, clinical practice, and public health as well asfrom specialists in economics, demography, sociology, and other disciplines whose study elucidates the factorsinfluencing the emergence of infectious diseases.

EID will be published in English and will feature three types of articles: Perspectives, Synopses, and Dispatches.The purpose and requirements of each type of article are described in detail below.

Emerging Infectious DiseasesVolume 1 • Number 4 October–December 1995

Synopses

The Ascension of Wildlife Rabies: A Cause for Public Health Concern or Intervention?

107 Charles E. Rupprecht, Jean S.Smith, Makonnen Fekadu, andJames E. Childs

Diagnosis of Tuberculosis in Children: Increased Need for Better Methods

115 Ejaz A. Khan and Jeffrey R. Starke

Data Management Issues for Emerging Diseases and New Tools forManaging Surveillance and Laboratory Data

124 Stanley M. Martin and Nancy H.Bean

Dispatches

Helicobacter hepaticus, a Recently Recognized Bacterial Pathogen,Associated with Chronic Hepatitis and Hepatocellular Neoplasia inLaboratory Mice

129 Jerry M. Rice

Hemolytic Uremic Syndrome Due to Shiga-like Toxin ProducingEscherichia coli O48:H21 in South Australia

132 Paul N. Goldwater and Karl A.Bettelheim

Does Treatment of Bloody Diarrhea due to Shigella dysenteriae Type 1 with Ampicillin Precipitate Hemolytic Uremic Syndrome?

134 Abdulaziz A. A. Bin Saeed, HassanE. El Bushra, and Nasser A.Al-Hamdan

An Outbreak of Hemolytic Uremic Syndrome Associated withAntibiotic Treatment of Hospital Inpatients for Dysentery

138 Sami Al-Qarawi, Robert E.Fontaine, and Mohammed-SaeedAl-Qahtani

Epidemic Cholera in the New World: Translating Field Epidemiologyinto New Prevention Strategies

141 Robert V. Tauxe, Eric D. Mintz,and Robert E. Quick

Are North American Bunyamwera Serogroup Viruses EtiologicAgents of Human Congenital Defects of the Central Nervous System?

147 Charles H. Calisher and John L. Sever

Lymphocytic Choriomeningitis Virus: An Unrecognized Teratogenic Pathogen

152 Leslie L. Barton, C.J. Peters, andT.G. Ksiazek

Commentary

Hemolytic Uremic Syndrome 154 Mary Beers and Scott Cameron

News and Notes

Guidelines on the Risk for Transmission of Infectious Agents During Xenotransplants

156 Louisa E. Chapman

Emerging Infectious Diseases Featured at ICAAC/IDSA Meeting 156

Building a Geographic Information System (GIS) Public HealthInfrastructure for Research and Control of Tropical Diseases

156 Allen W. Hightower and Robert E. Klein

APHA Session Features Emerging Infections 157 Martin S. Favero

Southeast Asia Intercountry Consultative Meeting on Preventionand Control of New, Emerging, and Reemerging Infectious Diseases

158 Samlee Plianbangchang

Contents

The Ascension of Wildlife Rabies: A Cause for PublicHealth Concern or Intervention?

Charles E. Rupprecht, V.M.D., Ph.D., Jean S. Smith, M.S.Makonnen Fekadu, D.V.M., Ph.D., and James E. Childs, Sc.D.Centers for Disease Control and Prevention, Atlanta, Georgia, USA

The epidemiology of rabies in the United States has changed substantially during thelast half century, as the source of the disease has changed from domesticated animalsto wildlife, principally raccoons, skunks, foxes, and bats. Moreover, the changesobserved among affected wildlife populations have not occurred without human influ-ence. Rather, human attraction to the recreational and economic resources provided bywildlife has contributed to the reemergence of rabies as a major zoonosis. Althoughhuman deaths caused by rabies have declined recently to an average of one or two peryear, the estimated costs associated with the decrease in deaths amount to hundredsof millions of dollars annually. In future efforts to control rabies harbored by free-ranginganimal reservoirs, public health professionals will have to apply imaginative, safe, andcost-effective solutions to this age-old malady in addition to using traditional measures.

Rabies virus is the type species (serotype 1) ofthe Lyssavirus genus, a group of morphologicallysimilar, antigenically and genetically related,negative-stranded RNA viruses, with a nearglobal distribution (1). The lyssaviruses (Table 1)are well adapted to particular mammalian spe-cies (2) and rarely initiate panzootics. The publichealth threat of rabies as a preeminent zoonosisrelates to the acute, incurable encephalitis thatresults from transmission of the virus by the biteof an infected animal. An estimated 40,000 to100,000 human deaths are caused by rabies eachyear worldwide; in addition, millions of persons,primarily in developing countries of the subtropi-cal and tropical regions (3), undergo costly postex-posure treatment (PET). Although the number ofhuman rabies cases has been significantly re-duced in the United States, the total number ofanimal rabies cases approached historical limitsin 1993. To appreciate the public health signifi-cance that lyssaviruses continue to play as per-sistent and emerging infectious agents, one mustunderstand certain human activities, such as re-cent animal translocations (i.e., the natural orpurposeful change by humans of the normalhome range or geographic distribution of an ani-mal) and animal ecology.

Historical PerspectivesThe history of rabies in the New World reflects

the interaction of chance, evolutionary con-straint, ecologic opportunism, and human sur-veillance activities. Rabies may have existed inthe United States before European colonizationand the introduction of domestic animals incubat-ing the disease. Various pathogens could havemigrated during the exchanges of fauna and hu-man populations over the Bering Strait some50,000 years ago; folklore of a rabies-like maladyamong native people throughout the PacificNorthwest supports this notion (4). Records at thetime of the Spanish conquest in Middle Americaassociate vampire bats with human illness (5). Ifchiropteran rabies viruses were present and wellestablished in the New World at the time of con-tinental interchange, terrestrial virus counter-parts also could have been present. Nonetheless,the first indication of terrestrial rabies did notsurface until 1703 in what is now California (5).Dog and fox rabies outbreaks, reported commonlyin the mid-Atlantic colonies throughout the late1700s (4), were probably exacerbated by the intro-duction of dogs and red foxes (Vulpes vulpes),imported for British-style fox hunting, through-out New England in the 1800s; fox rabies epizo-otics ensued and spread to the eastern UnitedStates by the 1940s to 1950s (5,6). Skunk rabiesreports were also frequent throughout the west-ern states by the 19th century, and they werereplete with cowboy tales of “phobey cats” (5).

Address for correspondence: Charles E. Rupprecht, Centersfor Disease Control and Prevention, 1600 Clifton Rd., MSG33, Atlanta, GA 30333, USA; fax 404-639-1058; [email protected].

Synopses

Vol. 1, No. 4 — October-December 1995 107 Emerging Infectious Diseases

Although individual reports document a highincidence of dog rabies at the beginning of the lastcentury, no national surveillance system existed.Human deaths from rabies in the United Stateswere not commonly reported; the highest officialrecord was of 143 cases, from a survey of deathcertificates in 1890. During 1938, when rabies inhumans and other animals became a nationallyreportable disease, the total number of rabiescases reported was 9,412 per year (mostly indomesticated species), with 47 human deaths.These numbers are certainly underestimates,since surveillance was limited, and sensitivediagnostic tests for human and animal rabieswere not developed until the mid-1950s.

An epizootiologic transition began in theUnited States in the 1920s, when rabiesprevention efforts were no longer focused exclu-sively on human vaccination but began to include

programs for the control of rabies in dogs. Domes-tic animal cases gradually declined, largely as aresult of local dog rabies control programs thatincluded vaccination, stray animal removal, andleash and muzzle ordinances. However, as suchcases decreased, surveillance systems designed totrack the source of infection for residual domesticanimal foci detected increased cases in wild spe-cies. By 1960, rabies was diagnosed more fre-quently among wildlife than among domesticatedanimals. In 1971, rabies was reported for the firsttime from all 48 contiguous states and Alaska.Skunks (primarily the striped skunk, Mephitismephitis) formed the major animal reservoir from1961 to 1989, until they were unexpectedly sup-planted by the raccoon (Procyon lotor) during therabies outbreak in the mid-Atlantic and north-eastern states (7). This epizootic is believed tohave started during the late 1970s by the

Table 1. Recognized members of the genus Lyssavirus, family Rhabdoviridae

Lyssavirus Reservoir History

Rabies Found worldwide, except for a few islandnations, Australia, and Antarctica.Endemic and sometimes epidemic in awide variety of mammalian species,including wild and domestic canids,mustelids, viverrids, and insectivorousand hematophagous bats; >25,000 humancases/year, almost all in areas ofuncontrolled domestic dog rabies.

Descriptions of clinical disease in Greekand Roman documents. In the late 1800s,Pasteur attenuated the virus by serialpassage and desiccation to vaccinatehumans and animals. Pathognomonicinclusions in nerve cells described byNegri in 1903. An immunofluorescencetest for rabies viral antigen developed inthe 1950s.

Lagosbat Unknown, but probably fruit bats. 10cases identified to date, including 3 indomestic animals, in Nigeria, SouthAfrica, Zimbabwe, Central AfricanRepublic, Senegal, and Ethiopia. Noknown human deaths.

Isolated in 1956 from brain of Nigerianfruit bats (Eidolon helvum) at LagosIsland, Nigeria, but not characterizeduntil 1970; 3 cases in domestic animalsinitially diagnosed as rabies, but weakimmunofluorescence led to suspicion of“rabies-related” virus, later confirmed bytyping with monoclonal antibodies ornucleotide sequence analysis. Marginalcross-protection with rabies vaccines.

Mokola Unknown, but probably an insectivore orrodent species. Cases identified inNigeria, South Africa, Cameroon,Zimbabwe, Central African Republic, andEthiopia; 17 cases known, including 9domestic animals and 2 human cases.

First isolated from Crocidura sp. shrewstrapped in Mokola Forest near Ibadan,Nigeria, in 1968. Characterized in 1970.Like Lagos bat virus, evidence of infectionwith Mokola was recognized only by poorreaction with anti-rabies reagents. 7domestic animal cases in Zimbabwe in1981 and 1982 prompted serologic surveyand identification of antibodies to Mokolain rodents, especially bushveld gerbils(Tatera leucogaster). No cross-protectionwith rabies vaccines.

Synopses

Emerging Infectious Diseases 108 Vol. 1, No. 4 — October-December 1995

translocation of infected animals from a south-eastern focus of the disease.

The epidemiology of human rabies has alsochanged considerably over the last 50 years (8,9).From 1946 to 1965, 70% to 80% of human rabiescases occurred after a known exposure (mostoften a dog bite), and 50% of the cases before 1975occurred after treatment with suboptimal vac-cines. Over the last decade, 80% of rabies-relatedhuman deaths were among persons who had nodefinitive history of an animal bite (Table 2), andnone resulted from postexposure prophylaxis fail-ures. Almost all the recent human cases occurredafter an animal exposure that was unrecognizedby the patient as carrying a risk for rabies infec-tion. The apparent source of human rabies hasalso changed: 14 of the 18 cases acquired in theUnited States since 1980 involved rabies variantsassociated with insectivorous bats (10).

The latest report, in March 1995, typifies re-cent trends. A bat, subsequently found to be rabid,was found in the bedroom of a 4-year-old girl inWashington State. The child denied any contactwith the bat, and no postexposure treatment wasinitiated. A bat-associated rabies virus variantwas later identified in biopsy specimens from the

Table 1. (continued)

Lyssavirus Reservoir History

Duvenhage Unknown, but probably insectivorousbats. Cases identified in South Africa,Zimbabwe, and Senegal; 4 cases known,including 1 human death. No cases indomestic animals.

First identified in 1970 in rabies-likeencephalitis in man bitten by aninsectivorous bat near Pretoria, SouthAfrica. Virus named after the victim.Although Negri bodies detected inhistologic examination of brain tissue,negative immunofluorescence tests led tosuspicion of rabies-related virus,subsequently confirmed by antigenic andgenetic typing. Marginal cross-protectionwith rabies vaccines.

European batLyssavirus 1(EBLV1)

European insectivorous bats (probablyEptesicus serotinus); >400 cases in bats. 1confirmed human case in 1985 and asuspect case in 1977. No known domesticanimal cases.

Although cases in European bats werereported as early as 1954, identification ofthe virus was not attempted until 1985,when the first of 100 infected bats wasreported in Denmark and Germany.Almost all cases are in the commonEuropean house bat, E serotinus.Marginal cross-protection with rabiesvaccines.

European batLyssavirus 2(EBLV2)

European insectivorous bats (probablyMyotis dasycneme); 5 cases identified,including 1 human death. No knowndomestic animal cases.

First identified in isolate from Swiss batbiologist who died of rabies in Finland.Marginal cross-protection with rabiesvaccines.

Table 2. Human rabies cases in the United States by exposurecategory, 1946-1995*

Exposure source CaseYears Domestic Wildlife Other Unknown (%) total

1946-1955 86 8 0 26 (22) 120

1956-1965 21 7 0 10 (26) 38

1966-1975 6 7 1 2 (13) 16

1976-1985 6 1 2 11 (55) 20

1986-1995* 2 2 0 14 (78) 18* Through Oct. 1995.

Synopses


child and from the bat’s carcass (11). Despite thecurrent prominence of raccoons as the largestwildlife reservoir in the United States (12), nodocumented human rabies cases have beenassociated with this ubiquitous carnivore.

The Cost of PreventionRabies prevention and control strategies in the

United States have succeeded in lowering thenumber of human rabies deaths to an average ofone to two per year. However, the reason for thislow mortality level is a prevention program esti-mated to cost $230 million to $1 billion per year(13-15). This cost is shared by the private sector(primarily the vaccination of companion animals)and by the public (through animal control pro-grams, maintenance of rabies laboratories, andsubsidizing of rabies PET).

Accurate estimates of these expenditures arenot available. The number of PETs given an-nually in the United States is unknown, althoughthe total must be substantially greater than theminimum of 20,000 estimated in 1980 to 1981 (16)when vaccine distribution was more tightlyregulated. As rabies becomes epizootic or enzooticin a region, the number of PETs increases (17).Although the cost varies, a course of rabies immu-noglobulin and five doses of vaccine given over a4-week period typically exceeds $1,000. Potentialexposure to a single rabid kitten in New Hamp-shire recently led to the treatment of more than650 persons at an estimated cost of $1.5 million(18). Surveillance-related costs also rise as rabiesbecomes entrenched in wildlife. During 1993, theNew York State rabies diagnostic laboratory re-ceived approximately 12,000 suspected animalsubmissions. This compares with approximately3,000 submissions in 1989, before raccoon rabiesbecame epizootic. In New Jersey, rabies preven-tion expenditures in two counties increased from$768,488 in 1988, before the raccoon epizootic, to$1,952,014 in 1990, the first full year of theepizootic (15); vaccination of pet animals ac-counted for 82% of this total. Vaccinated domesticanimals are normally administered a booster vac-cine dose after a known or suspected rabid animalexposure (19). This further increases costs, aswildlife rabies epizootics escalate. The cost perhuman life saved from rabies ranges from ap-proximately $10,000 to $100 million, dependingon the nature of the exposure and the probabilityof rabies in a region (20).

What’s more, most economic analyses do nottake into account the psychological traumacaused by human exposure to rabies, the sub-sequent euthanasia of pets, or the loss of wildliferesources during rabies outbreaks. Rabies inwildlife has now reached historically high levelsin the United States (12), and the costs of prevent-ing human rabies are mounting.

Human Influences and the Role of TranslocationThe colonization of the New World had a pro-

found effect upon native fauna and consequentrabies epizootiology. Large-bodied carnivores,such as bears, cougars, wolves, and wolverines,were perceived as dangerous and killed outright.A few Carnivora have persisted and flourished.For example, the coyote (Canis latrans), a highlyadaptable canid and the subject of many unsuc-cessful control programs, has been gradually ex-panding its range northward and eastward.Despite their widespread distribution and abun-dance (even in suburban neighborhoods), rabidcoyotes have been reported rarely andsporadically, except for a brief period from 1915to 1917, when an extensive outbreak occurred inportions of Utah, Nevada, California, and Oregon.

While dog rabies has been largely controlled, aregion of southern Texas that borders Mexico haspersisted as a focus of both dog and coyote rabies.The number of cases of coyote rabies has gradu-ally risen in this area since the late 1980s, ac-counting for 46 of the 50 cases of coyote rabiesreported in the United States during 1991, 70 of75 cases in 1992, and 71 of 74 cases in 1993 (12).The outbreak of coyote rabies has spread to thevicinity of San Antonio. One of the dangers of thisoutbreak is the continued spillover into the do-mestic dog population (21); at least 25 rabid dogswere reported from the area in 1991, 41 in 1992,and 54 in 1993 (12). Human rabies closely paral-lels the disease in domestic animals; at least twohuman deaths (in 1991 and 1994), probably dueto coyote-dog interactions, have been associatedwith this canid outbreak in Texas (10,22).

The translocation of infected coyotes from thesouth Texas focus is believed to be responsible forthe transmission of this rabies variant to dogs inat least two other states: a single hunting dog inAlabama during 1993 (12) and at least sevencases of apparent dog-to-dog rabies transmissionin Florida in 1994 (21). Expanded surveillancesimilar to that done in 1977 with the raccoon

Synopses


rabies focus in the mid-Atlantic region (7) is war-ranted for this canid virus. In this effort, statehealth departments should monitor unusual oc-currences (such as the increased submission ofcanid specimens to the diagnostic facility), track-ing of their time and location, and establishmentof suitable public health interventions. Thesewould include restricting further animal move-ments and enforcing mandatory companion ani-mal rabies vaccination. Assessing control effortsis an important component of any intervention.In addition to the problems posed by the emer-gence of the coyote as a reservoir for rabies, thepotential translocation of other species should berecognized.

Since the transmission of rabies by a bat wasfirst reported in 1953, rabid insectivorous batshave caused an average of 700 to 800 cases annu-ally, and have been found throughout the UnitedStates, excluding Alaska and Hawaii (12). Thediscovery of these cases, coincident with themarked reduction of canine rabies cases, has af-forded a certain epidemiologic luxury to enhancesurveillance among wildlife. Similar to theCarnivora, the chiropteran families most impor-tant in rabies perpetuation (e.g., Vespertilionidae,Molossidae) have several species that are highlyadaptable, abundant, and widespread. Rabies vi-rus variants maintained by insectivorous batsappear to be exchanged largely independentlyfrom those in terrestrial mammalian reservoirs(23), despite documented spillovers. A similarepidemiologic situation exists among Europeanbats, but with Lyssavirus genotypes (24) that canbe readily differentiated from New World rabiesisolates. The role of bats in Africa (25,26) in Lys-savirus maintenance is less clear (Table 1). Infec-tions with non-rabies lyssaviruses have resultedin rabies vaccine failures (27). Such infectionsraise the specter of potentially serious public healthconsequences if introduced and subsequently es-tablished in susceptible bat populations. Howprobable is this scenario?

The distances between Africa, Eurasia, PacificOceania, and the New World mitigate against thedispersal, migration, and introduction of healthybats without human intervention (28). However,several recent events illustrate the opportunityfor the transoceanic transfer of rabies-infectedbats. In March 1986, researchers from Canadainadvertently shipped a big brown bat (Eptesicusfuscus) that was incubating rabies virus to

colleagues in Tubingen, Germany. When the batbecame ill and was euthanized, a diagnosis ofrabies was made (29). A similar event occurredwhen Boston researchers collected a dozen wildbig brown bats from Massachusetts during July1994 and exported them to researchers in Den-mark. By December 1994, six of the imported batshad died and were confirmed as positive for rabiesvirus by the Danish Veterinary Services, StateInstitute for Virus Research (L. Miller, pers.comm.).

Commercial enterprises also serve as vehiclesfor the accidental translocation of animals in-fected with rabies virus. The first confirmed non-indigenous case of rabies in Hawaii resulted fromthe accidental introduction of a big brown bat(30). In March 1991, a bat was captured within atransport container unloaded from a ship inHonolulu harbor. The container held automobilesfrom Michigan loaded into the container ship inCalifornia. The local department of health labo-ratory diagnosed rabies; this was later confirmed,and the virus was characterized antigenically atthe Centers for Disease Control and Prevention.The strain was a variant common to E. fuscus inthe midwestern and western United States. Noneof the three instances cited above appear to haveresulted in secondary cases or establishment ofthe virus in foreign animal populations.

No unintended importations of non-rabies lys-saviruses to the United States have been docu-mented. The likelihood of accidental introduction,escape, survival, and perpetuation of infected ex-otic bat species into the United States is remote.However, other more recent deliberate transloca-tion activities may significantly enhance theprobability of such introductions.

During 1994, a number of improperly issuedfederal permits allowed as many as several thou-sand wild bats to be imported to the United Statesfor sale in the commercial pet trade. Theseanimals were primarily Egyptian tomb bats(Rousettus aegyptiacus), although several otherbat species were imported as well. Sales of im-ported bats (and their offspring) to private collec-tors or as pets in the United States are prohibited,according to the Foreign Quarantine Regulations(42 CFR 71.54). Animals that may be vectors ofdiseases of public health concern are eligible forentrance only for restricted uses at accreditedzoos or research institutions, where contact withthe general public is limited. Imported bats that

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will be legally displayed normally undergo anextended quarantine period.

Although no reports of lyssaviruses isolatedfrom Egyptian fruit bats exist, active surveillancefor such viruses has not been conducted. Thesebats are relatively common and widespreadthroughout the area that extends from Turkeyand Cyprus to Pakistan, the Arabian peninsula,Egypt, and most of sub-Saharan Africa (31). Be-cause they may roost by the thousands in a widevariety of habitats, there is ample opportunity forinteraction with other Chiroptera, such as thewidely distributed straw-colored (Eidolonhelvum) or epauletted (Epomophorus wahlbergi)fruit bats; both of these species have been impli-cated in Lyssavirus epizootiology in Africa (25,26).The adaptability of Egyptian fruit bats should bea cause for concern because of the potential forsurvival and interaction among indigenous batfauna, particularly in the southern United States.Additionally, beyond the obvious public healthrisks and foreign animal disease introduction,imported bat species should not be released intothe wild because they may cause serious harm tolocal agriculture and may displace native species.

Bats serve many critical ecologic functionsworldwide and generally avoid contact with hu-mans. However, they may be infected with manypathogens without demonstrating obvious clini-cal signs of infection. When bats are placed in aprivate household or pet shop, the hazard of dis-ease transmission to humans is greatly increased.Persons currently possessing imported batsshould be advised not to display them in settingswhere human contact can occur.

InterventionWidespread, sustained population reduction of

mammalian reservoirs to eliminate rabies is notjustified (32) for ecologic, economic, and ethicalreasons. Given the multispecies complexity andconsiderable geographic areas affected by wildliferabies, and the opportunities for translocation,what alternative preventive strategies exist? Re-cent progress in implementing terrestrial wildliferabies control programs elsewhere in the worldhas public health relevance for the United States.Oral rabies vaccination of the red fox with vac-cine-laden baits is an integral aspect of rabiescontrol throughout southeastern Canada andEurope, where more than 75 million doses ofvaccine have been distributed over 5 million km2

during the past two decades (33). Consequently,rabies incidence among wild and domestic ani-mals has fallen, as have PETS for human rabies.

The raccoon rabies epizootic in the easternUnited States provided renewed impetus for re-considering oral vaccination technology, first con-ceived at the Center for Disease Control in the1960s (34). The shift of the vaccination and bait-ing methods from a fox model to the raccooninvolved extensive field and laboratory researchduring the 1980s. The existing attenuated rabiesvaccines for foxes were shown to be less effectivefor raccoons and other carnivores (35,36). Addi-tionally, studies of new candidate vaccines raisedsafety issues regarding vaccine-induced diseasein wildlife (36).

In 1983, a vaccinia-rabies glycoprotein (V-RG)recombinant virus vaccine was developed (37)that has proven to be an effective oral immunogenin raccoons and various other important reservoirspecies (38); vaccine advantages include im-proved thermostability and an inability to causerabies. (Only the gene for the surface glycoproteinof a vaccine strain of rabies virus was included inthe recombinant virus.) When vaccine-laden baitsare offered under natural conditions, contact withthem by nontarget wildlife species cannot be to-tally excluded. However, studies of V-RG virushave shown no vaccine-associated morbidity, mor-tality, or gross pathologic lesions in more than 40warm-blooded vertebrate species examined.Moreover, with rare exceptions, there has been nocontact-transfer of vaccine between vaccinatedand control animals housed together (38); viralrecovery has been limited to a few anatomicalsites over a 48-h interval (39).

While laboratory evaluations of target andnontarget species proceeded during 1987 to 1989,small-scale trials of V-RG were conducted in Bel-gium and France, with promising results (40).The first North American V-RG vaccine field trialbegan on August 20, 1990, on Parramore Islandoff the eastern shore of Virginia (41,42). Thislimited field trial demonstrated vaccine safety.Efficacy was also suggested: more than 80% offield-vaccinated raccoons survived a severe labo-ratory rabies challenge (7 months after V-RGrelease) to which more than 90% of control rac-coons succumbed (43).

A 1991 Pennsylvania study site closely ap-proximated the ecologic communities of the east-ern United States targeted for use of V-RG

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vaccine, while still maintaining relative biosecu-rity through its geographic barriers. The study atthis site evaluated the rate of vaccine-laden baitcontact and potential vaccine-related adverse ef-fects among nonraccoon species, including ro-dents, carnivores, insectivores, and opossum.Raccoons and other furbearers demonstrated noadverse effects associated with vaccine contact.Examination of more than 750 nontarget indi-viduals, representing 35 species, failed to demon-strate gross lesions suggestive of V-RG contact.

After these safety trials, the first efficacy fieldexperiments began in New Jersey during 1992(44). Between spring 1992 and autumn 1994,more than 100,000 vaccine-laden fishmeal poly-mer baits were distributed by hand and helicopterover an area of 56,000 hectares. This trial at-tempted to create a population of immunized rac-coons across the northern Cape May Peninsula toprevent the spread of epizootic raccoon rabiesfrom affected portions of the state. Surveillancedemonstrated a significant decrease in the rate ofspread and overall rabies incidence in the targetand other monitored areas (44), suggesting thepotential effectiveness of this strategy.

In the United States, oral vaccination of rac-coons is now under way in Massachusetts (45),New York (46), and Florida, and an experimentalextension of the program to coyotes is under wayin south Texas. However, the future of such vac-cination for wildlife in the United States may beseriously questioned. For oral vaccination tobecome an adjunct to traditional methods, thefollowing major questions need to be answered:1) What is the relationship between animal popu-lation density and the minimum density of vac-cine/baits needed? 2) What level of herd immunityis necessary to eliminate rabies under variousenvironmental circumstances? 3) What bait dis-tribution techniques are optimal? 4) How canthese methods be generalized from foxes and rac-coons to other species, such as skunks, mongoosesand dogs? 5) What long-term funding sources areavailable? 6) What are the various costs of rabiescontrol and prevention methods? Given the prob-lems inherent in wildlife control, the greater issueof extending these methods to the control of dograbies in the developing world will be a challengewell into the next century.

Dr. Rupprecht is chief of the Rabies Section, Ms.Smith is a research microbiologist, Dr. Fekadu is aresearch veterinary medical officer, and Dr. Childs ischief of the Epidemiology Section, Viral and RickettsialZoonoses Branch, Division of Viral and RickettsialDiseases, National Center for Infectious Diseases,Centers for Disease Control and Prevention, Atlanta,Georgia.

AcknowledgmentThe authors gratefully acknowledge the technical expertiseof the staff of the Rabies and Epidemiology Sections, Viraland Rickettsial Zoonoses Branch, Division of Viral andRickettsial Diseases, National Center for InfectiousDiseases, Centers for Disease Control and Prevention,without whose assistance this work would not have beenpossible.

References 1. World Health Organization. World survey of rabies 28

for the year 1992. Geneva: World Health Organiza-tion, 1994.

2. Wandeler A, Nadin-Davis SA, Tinline RR, RupprechtCE. Rabies epizootiology: an ecological and evolution-ary perspective. In: Rupprecht CE, Dietzschold B,Koprowski H, editors. Lyssaviruses. New York: Sprin-ger-Verlag, 1994:297-324.

3. Meslin FX, Fishbein DB, Matter HC. Rationale andprospects for rabies elimination in developing coun-tries. In: Rupprecht CE, Dietzschold B, Koprowski H,editors. Lyssaviruses. New York: Springer-Verlag,1994:1-26.

4. Winkler WG. Fox rabies. In: Baer GM, editor. Thenatural history of rabies. 1st ed. New York: AcademicPress, 1975:3-22.

5. Baer GM. Rabies—an historical perspective. Infec-tious Agents and Disease 1994;3:168-80.

6. Carey AB, Giles RH, McLean RG. The landscapeepidemiology of rabies in Virginia. Am J Trop Med Hyg1978;27:573-80.

7. Rupprecht CE, Smith JS. Raccoon rabies—the re-emergence of an epizootic in a densely populated area.Semin Virol 1994;5:155-64.

8. Held JR, Tierkel ES, Steele JH. Rabies in man andanimals in the United States, 1946-65. Public HealthRep 1967;82:1009-18.

9. Anderson LJ, Nicholson KG, Tauxe RV, Winkler WG.Human rabies in the United States, 1960 to 1979:epidemiology, diagnosis, and prevention. Ann InternMed 1984;100:728-35.

10. Centers for Disease Control and Prevention. Humanrabies—Alabama, Tennessee, and Texas, 1994.MMWR 1995;44:269-72.

11. Centers for Disease Control and Prevention. Humanrabies—Washington state, 1995. MMWR 1995;44:625-7.

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12. Krebs JW, Strine TW, Smith JS, Rupprecht CE,Childs JE. Rabies surveillance in the United Statesduring 1993. J Am Vet Med Assoc 1994;205:1695-709.

13. Stehr-Green JK, Schantz PM. The impact of zoonoticdiseases transmitted by pets on human health and theeconomy. Vet Clin North Am Small Anim Pract1987;17:1-15.

14. Fishbein DB, Arcangeli S. Rabies prevention in pri-mary care: a four-step approach. Postgrad Med1987;82:83-90.

15. Uhaa IJ, Dato VM, Sorhage FE, et al. Benefits andcosts of using an orally absorbed vaccine to controlrabies in raccoons. J Am Vet Med Assoc 1992;201:1873-82.

16. Helmick CG. The epidemiology of human rabiespostexposure prophylaxis, 1980-1981. JAMA1983;250:1990-6.

17. Centers for Disease Control and Prevention. Raccoonrabies epizootic: United States, 1993. MMWR1994;43:269-73.

18. Centers for Disease Control and Prevention. Masstreatment of humans exposed to rabies—New Hamp-shire, 1994. MMWR 1995;44:483-6.

19. Centers for Disease Control and Prevention. Compen-dium of animal rabies control, 1995. MMWR1995;44:(RR-2):1-9.

20. Fishbein DB, Robinson LE. Rabies. N Engl J Med1993;329:1632-8.

21. Centers for Disease Control and Prevention. Translo-cation of coyote rabies—Florida, 1994. MMWR1995;44:580-1, 7.

22. Centers for Disease Control and Prevention. Humanrabies—Texas, Arkansas, and Georgia, 1991. MMWR1991;40:765-9.

23. Smith JS, Orciari LA, Yager PA. Molecular epidemiol-ogy of rabies in the United States. Semin Virol (inpress).

24. Bourhy H, Kissi B, Lafon M, Sacramento D, Tordo N.Antigenic and molecular characterization of bat ra-bies virus in Europe. J Clin Microbiol 1992;30:2419-26.

25. Swanepoel R, Barnard BJH, Meredith CD, et al. Ra-bies in southern Africa. Onderstepoort J Vet Res1993;60:325-46.

26. King AA, Meredith CD, Thomson GR. The biology ofsouthern Africa lyssavirus variants. In: RupprechtCE, Dietzschold B, Koprowski H, editors. Lys-saviruses. New York: Springer-Verlag, 1994:267-96.

27. Foggin CM. Mokola virus infection in cats and a dogin Zimbabwe. Vet Rec 1983;113:115.

28. Wiles GJ, Hill JE. Accidental aircraft transport of abat to Guam. J Mamm (full title) 1986;67:600-1.

29. World Health Organization Collaborating Center forRabies Surveillance and Research. Bat rabies cases inthe Federal Republic of Germany. World Health Or-ganization Rabies Bulletin Europe 1986;10:8-9.

30. Sasaki DM, Middleton CR, Sawa TR, Christensen CC,Kobayashi GY. Rabid bat diagnosed in Hawaii. Ha-waii Med J 1992;51:181-5.

31. Nowak RM. Walkers mammals of the world. 5th ed.Baltimore: Johns Hopkins University Press,1991:198.

32. Debbie JG. Rabies control of terrestrial wildlife bypopulation reduction. In: Baer GM, editor. The natu-ral history of rabies. 2nd ed. Boca Raton, FL: CRCPress, 1991:477-84.

33. World Health Organization. Oral immunization offoxes in Europe in 1994. Wkly Epidemiol Rec1995;70:89-91.

34. Baer GM. Oral rabies vaccination: an overview. RevInfect Dis 1988;10 (Suppl 4):S644-8.

35. Rupprecht CE, Dietzschold B, Cox JH, Schneider L.Oral vaccination of raccoons (Procyon lotor) with anattenuated (SAD-B19) rabies virus vaccine. J WildlDis 1989;25:548-54.

36. Rupprecht CE, Charlton KM, Artois M, et al. Ineffec-tiveness and comparative pathogenicity of attenuatedrabies virus vaccines for the striped skunk (Mephitismephitis). J Wildl Dis 1990;26:99-102.

37. Wiktor TJ, Macfarlan RI, Reagan KJ, et al. Protectionfrom rabies by a vaccinia virus recombinant contain-ing the rabies virus glycoprotein gene. Proc Natl AcadSci USA 1984;81:7194-8.

38. Rupprecht CE, Hanlon CA, Hamir AN, Koprowski H.Oral wildlife rabies vaccination: development of arecombinant virus vaccine. Transactions of the NorthAmerican Wildlife Natural Resources Conference1992;57:439-52.

39. Rupprecht CE, Hamir AN, Johnston DH, KoprowskiH. Efficacy of a vaccinia-rabies glycoprotein recombi-nant virus vaccine in raccoons (Procyon lotor). RevInfect Dis 1988;10 (4 Suppl):S803-9.

40. Aubert MFA, Masson E, Artois M, Barrat J. Oralwildlife rabies vaccination field trials in Europe, withrecent emphasis on France. In: Rupprecht CE,Dietzschold B, Koprowski H, editors. Lyssaviruses.New York: Springer-Verlag, 1995:219-44.

41. Hanlon CA, Hayes DE, Hamir AN, et al. Proposedfield evaluation of a rabies recombinant vaccine forraccoons Procyon lotor: site selection target speciescharacteristics and placebo baiting trials. J Wildl Dis1989;4:555-67.

42. Hanlon CA, Buchanan JR, Nelson E, et al. A vaccinia-vectored rabies vaccine field trial:ante- and post-mor-tem biomarkers. Rev Sci Tech 1993;99-107.

43. Rupprecht CE, Hanlon CA, Niezgoda M, BuchananJR, Diehl D, Koprowski H. Recombinant rabies vac-cines: efficacy assessment in free-ranging animals.Onderstepoort J Vet Res 1993;60:463-8.

44. Roscoe DE, Holste W, Niezgoda M, Rupprecht CE.Efficacy of the V-RG oral rabies vaccine in blockingepizootic raccoon rabies. Presented at the 5th AnnualInternational Meeting of Rabies in the Americas, Ni-agara Falls, Ontario, Canada, 1994, Abstract, p.33.

45. Robbins AH, Niezgoda M, Levine S, et al. Oral rabiesvaccination of raccoons (Procyon lotor) on the CapeCod Isthmus, Massachusetts. Presented at the 5thAnnual International Meeting of Rabies in the Ameri-cas, Niagara Falls, Ontario, Canada, 1994; Abstract,p. 29.

46. Hanlon CA, Trimarchi C, Harris-Valente K, DebbieJG. Raccoon rabies in New York State: epizootiology,economics, and control. Presented at the 5th AnnualInternational Meeting of Rabies in the Americas,Niagara Falls, Ontario, Canada, 1994; Abstract, p.16.

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Diagnosis of Tuberculosis in Children:Increased Need for Better Methods

Ejaz A. Khan, M.D., and Jeffrey R. Starke, M.D.Baylor College of Medicine, Houston, Texas, USA

In the last decade tuberculosis (TB) has reemerged as a major worldwide public healthhazard with increasing incidence among adults and children. Although cases amongchildren represent a small percentage of all TB cases, infected children are a reservoirfrom which many adult cases will arise. TB diagnosis in children usually follows discoveryof a case in an adult, and relies on tuberculin skin testing, chest radiograph, and clinicalsigns and symptoms. However, clinical symptoms are nonspecific, skin testing and chestradiographs can be difficult to interpret, and routine laboratory tests are not helpful.Although more rapid and sensitive laboratory testing, which takes into account recentadvances in molecular biology, immunology, and chromatography, is being developed,the results for children have been disappointing. Better techniques would especiallybenefit children and infants in whom early diagnosis is imperative for preventingprogressive TB.

Despite the availability of effective preventivemeasures and chemotherapy, the prevalence oftuberculosis (TB) is increasing in the developingworld and in much of the industrialized world aswell (1-4). According to World Health Organiza-tion (WHO) estimates, in 1990 there were 8 mil-lion new cases of TB and 3 million deaths due tothe disease worldwide; 1.3 million new cases and450,000 deaths were among children under 15years of age (5). WHO projects that 90 million newcases and 30 million deaths–including 4.5 milliondeaths among children–will occur in the 1990s(6,7). In developing countries, the risk for TBinfection and disease is relatively uniform in thepopulation; annual rates of infection often exceed2% (5,6). In industrialized countries, risk is moreuneven and depends on the individual’s past orpresent activities and exposure to persons at highrisk for the disease (Table 1). From 1987 to 1991,the number of TB cases among children under 5years of age in the United States increased by49% from 674 cases to 1006 (8). Although casesamong children represent a small percentage ofall TB cases, infected children are a reservoirfrom which many adult cases will arise. The riskfor infection by Mycobacterium tuberculosisamong children depends primarily on the level ofrisk of developing infectious TB for the adults in

their immediate environment, especially theirhousehold. Because most current diagnostic testsfor TB infection and disease have low specificityand therefore low positive predictive values,epidemiologic investigation continues to be im-portant in establishing the diagnosis of TB inchildren. In industrialized countries, cliniciansand public health professionals in TB servicesmust always ask: Has the child been exposed toan adult with infectious pulmonary TB?

Natural History of TB in ChildrenThe natural history of TB in children follows a

continuum; however, it is useful to consider threebasic stages: exposure, infection, and disease (1).Exposure implies that the child has had recentand substantial contact with an adult or adoles-cent who has suspected or confirmed contagiouspulmonary TB (a source case). Exposed childrenare usually identified during followup investiga-tions for persons with suspected pulmonary TBby public health workers (9); the child’s tuberculinskin test (TST) is nonreactive, the results of thechest radiograph are normal, and the child is freeof physical signs or symptoms of TB. Someexposed children are infected with M. tubercu-losis . The cl inician cannot know immedi-ately which exposed children are infected becausethe development of delayed-type hypersensitivityto tuberculin may take up to 3 months. Unfortu-nately, in children under 5 years of age, severeTB—especially meningeal and disseminated

Address for correspondence: Jeffrey R. Starke, TexasChildren’s Hospital, MC 3-2371, 1102 Bates Street,Houston, TX 77030, USA; fax: 713-770-4347; [email protected].

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disease—can occur in fewer than 3 months, beforethe TST becomes reactive (10). Young children inthe exposure stage should receive chemotherapy,usually isoniazid, until infection can been ex-cluded.

TB infection is first signaled by a reactiveMantoux TST. In this stage, there are no signs orsymptoms, and the results of the chest radio-graph are either normal or show only fibroticlesions or calcifications in the lung parenchymaor regional lymph nodes. In developing countries,TB infection is rarely discovered and almostnever treated. In most industrialized countries,children with a positive TST receive isoniazid for6 to 12 months.

TB disease occurs when signs and symptomsor radiographic manifestations caused by M. tu-berculosis appear. Radiographic abnormalitiesand clinical manifestations in infected childrenprobably are influenced by the host inflammatoryreaction more than by the number of organisms.Studies show that in 40% to 50% of infants withuntreated TB infection disease develops within 1to 2 years (11). The risk decreases to 15% among

older children. In 25% to 35% of children TB isextrapulmonary and more difficult to confirmbacteriologically.

In adults, the distinction between TB infectionand disease is usually clear because most diseaseis caused by reactivation of dormant organismsyears after infection. Disease in adults is usuallyaccompanied by symptoms, and patients fre-quently are infectious. In children, who mostoften have primary disease, the interval betweeninfection and disease can be several months toseveral years, and radiographic abnormalitiesoften are not accompanied by symptoms; more-over, these children are rarely infectious. Themajor reason for separating infection from dis-ease in children is that the perception affects theapproach to treatment: infection is generallytreated with a single anti-TB drug, whereas ac-tive disease is treated with two or more drugs.The rationale for the difference in treatment isthat the likelihood of emergence of resistance toa drug increases as the bacillary population in-creases (3). This distinction is somewhat artificialin children since infection and primary diseaseare parts of a continuum. Because anti-TB medi-cations are well tolerated by children and arerelatively inexpensive in industrializedcountries, the usual paradigm of infection anddisease encourages overtreatment rather thanundertreatment. Asymptomatic lymphade-nopathy and mild lung parenchymal changes arelabeled and treated as disease.

When evaluating new diagnostic tests the ba-sic differences between the pathophysiology of TBin adults and children should be considered.Among children with recent TB infection, activemultiplication of mycobacteria occurs with orwithout the presence of radiographic abnormali-ties or clinical symptoms. For example, gastricaspirate cultures yield M. tuberculosis from asmall proportion of recently infected childrenwith normal chest radiographs. One can antici-pate that most diagnostic tests designed to detectM. tuberculosis in adults with TB disease will bepositive in some proportion of children who havewhat is usually called TB infection. It will takecareful consideration and investigation todetermine if and how the results of these newtests should influence the definitions and treat-ment of TB infection and disease in children.

Table 1. Persons at high risk for Mycobacterium tuberculosisinfection in industrialized countries

Persons likely to be exposed to or become infected withM. tuberculosis

• Close contacts of a person with infectious tu-berculosis (TB)

• Foreign-born persons from high-incidence ar-eas (e.g., Asia, Africa, Latin America)

• The elderly• Residents of long-term care facilities (e.g.,

correctional facilities and nursing homes)• Persons who inject drugs• Other groups identified locally as having in-

creased prevalence of TB (e.g., migrant farm workers or homeless persons)

• Persons who may have occupational expo-sure to TB

Persons at high risk of developing TB disease onceinfected

• Persons recently infected with M. tuberculo-sis (within the past 2 years)

• HIV-infected persons• Persons with immunosuppressing condi-

tions or medication use• Persons with a history of inadequately

treated TB • Infants

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Established Diagnostic Methods

Tuberculin Skin Test (TST)The Mantoux TST, which uses five tuberculin

units of purified protein derivative, is the stand-ard method for detecting infection by M. tubercu-losis. The reaction is measured as millimeters ofinduration after 48 to 72 hours. Since TST is theonly way to determine asymptomatic infection byM. tuberculosis, the false-negative rate cannot becalculated. A negative TST does not rule out TBdisease in a child. Approximately 10% of other-wise normal children with culture-proven TB donot react to tuberculin initially (12,13). Most ofthese children have reactive skin tests duringtreatment, which suggests that TB disease con-tributed to the immunosuppression. In mostcases, the anergy occurs to all antigens, but insome cases, reactions to tuberculin are negativebut reactions to other antigens remain positive(13). The rate of false-negative TST is higher inthose who are tested soon after becoming infectedwith severe TB; in children with debilitating orimmunosuppressive illnesses, malnutrition, orviral and certain bacterial infections; in infants;and if poor technique is used (1,14). The rate offalse-negative TST in children with TB who areinfected with human immunodeficiency virus(HIV) is unknown, but it is certainly higher than10%.

False-positive reactions to TST are often at-tributed to asymptomatic infection by environ-mental nontuberculous mycobacteria (NTM).Vaccination with M. bovis can cause transientreactivity to a subsequent TST, but the associa-tion is weaker than commonly recognized. Most–80% to 90% in several studies–children whoreceived BCG as infants have a nonreactive TSTat 5 years of age (15-17). Among older children oradolescents who receive BCG, most develop areactive skin test initially; however, by 10 to 15years postvaccination, 80% to 90% have lost tu-berculin reactivity (18,19). Skin test reactivitycan be boosted, probably by antigenic stimula-tion, by serial testing in many children and adultswho received BCG (20). Various factors determinethe TST reaction size after receipt of BCG (1).Many recipients of BCG have a reactive TSTbecause they are infected with M. tuberculosisand are at risk for disease, especially if they havehad recent contact with an infectious TB patient(18). In general, TST reaction should be

interpreted in the same manner for persons whohave received BCG (20) and for unvaccinatedpersons.

The relatively low sensitivity and specificity ofTST make the test very useful for persons at highrisk for TB infection or disease but undesirablefor use in persons at low risk (21,22). The predic-tive values of TST can be improved by varying thesize of induration considered positive according toepidemiologic risk factors for infection (Table 2).However, most of even 15-mm reactions in chil-dren at low risk are false-positive results, andtesting of persons at low risk should be discour-aged. Although the scheme in Table 2 is scientifi-cally and mathematically valid, it assumes thatthe clinician and family are willing and able todevelop an accurate history for TB risk factors forchildren and adults in their environments.

Clinical Signs and SymptomsTwo scenarios lead the clinician to suspect that

a child has TB disease. The first occurs when TBis considered during the differential diagnosis foran ill child. This is a common scenario in thedeveloping world but is less common in developedcountries. Infants are more likely to be sympto-matic than older children with pulmonary TB.The most common symptoms are cough, fever,wheezing, and failure to gain weight (13). Clinical

Table 2. Cut-off size of reactive area for a positive Mantouxtuberculin reaction

≥5 mm ≥10 mm ≥ 15 mm

Persons who had Foreign-born persons No risk factors contact with from high-prevalence infectious persons countries

Persons with an Residents of prisons, abnormal chest nursing homes, radiograph institutions

HIV-infected and Persons who inject drugs other immuno- suppressed persons

Persons with other medical risk factors

Health-care workers

Locally identified populations at high risk

Children in contact with adults at high risk

Infants

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signs are surprisingly meager, but rales andwheezes over the affected lung field are mostcommon. Signs and symptoms of extrapulmonaryTB are referable to the involved organ. The sen-sitivity and specificity of signs and symptoms areextremely low and can lead to both overdiagnosisand underdiagnosis when radiographs and othertests are not available.

The second scenario occurs when evaluating achild who has had significant contact with anadult with suspected or confirmed TB. Usuallythe TST is applied first and is reactive. A sub-sequent chest radiograph or physical examina-tion leads to discovery of early disease. The childis usually relatively asymptomatic. In the UnitedStates, about 50% of childhood TB cases are dis-covered in this manner (13).

Radiologic StudiesEvidence of pulmonary TB in chest radio-

graphs varies (23,24), but usually radiographsshow enlargement of hilar, mediastinal, or sub-carinal lymph nodes and lung parenchymalchanges (Figure 1). Most of the radiographic ab-normalities are caused by a combination of lungdisease and the mechanical changes induced bypartial or complete airway obstruction resultingfrom enlarging intrathoracic nodes. The mostcommon findings are segmental hyperinflationthen atelectasis, alveolar consolidation, intersti-tial densities, pleural effusion, and, rarely, a focalmass. Cavitation is rare in young children but ismore common in adolescents, who may developreactivation disease similar to that seen in adults.

The development of radiographic techniques,such as computed tomography (CT) scanning,illustrates some of the issues that arise whennewer and more sensitive diagnostic tests becomeavailable (24). A CT scan may show enlarged orprominent mediastinal or hilar lymph nodes insome children with recent TB infection and anormal chest radiograph (25). In the absence of aCT scan, the child’s disease stage would be calledTB infection, and single drug therapy would beused. Many studies, involving thousands of chil-dren have shown this treatment to be successful.However, when the CT scan shows mild ade-nopathy, the clinician may consider this findingindicative of TB disease and treat with severaldrugs, although this probably is not necessary inthe absence of drug resistance. These findingsreinforce the idea that pediatric TB is acontinuum, and the distinction between

infectionand disease is somewhat artificial. Thereis no current role for the CT scan in the evaluationof the asymptomatic TB-infected child with anormal chest radiograph. This scan can be helpfulin selected cases to demonstrate endobronchialdisease, pericardial invasion, early cavitation,and bronchiectasis resulting from pulmonary TBwhen the chest radiograph is abnormal but thepathologic process is not clear.

Mycobacterial Detection and IsolationDespite recent advances, early mycobacteri-

ologic diagnosis of TB still relies primarily onexamination of acid-fast-stained smears fromclinical specimens. It is the easiest, least expen-sive, and most rapid procedure for obtaining pre-liminary information. However, children under12 years of age with pulmonary TB rarely producesputum and are usually unable to expectoratevoluntarily. When sputum samples cannot be ob-tained, gastric aspirate samples are used fordetection and isolation of M. tuberculosis. Eventhough an acid-fast bacilli (AFB) stain of sputumis positive in up to 75% of adults with pulmonaryTB, fewer than 20% of children with TB have apositive AFB smear of sputum or gastric aspirate(26,27). The newer fluorochrome stains, such asauramine and rhodamine, are superior to classiccarbolfuchsin stains (28). The rates of positiveAFB stain from body fluids and tissues in childrenwith extrapulmonary TB also are low, and false-positive results caused by NTM disease are com-mon, especially in cervical lymph nodes.

Figure 1. Chest radiograph of a girl with pulmonarytuberculosis. Note the significant hilar adenopathy inassociation with atelectasis, the so-calledcollapse-consolidation lesion.

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For most children with pulmonary TB, cultureconfirmation is not needed. Diagnosis is made onthe basis of a positive TST, clinical and radio-graphic findings suggestive of TB, and history ofcontact with an adult source case. The drug-sus-ceptibility test results from the source case isolatecan be used to design the optimal treatment forthe child. However, cultures should be obtainedfrom the child if the source patient is unknown orhas a drug-resistant organism and if the child isimmunocompromised or has extrapulmonary TB.

The best specimen for culture from childrenwith suspected pulmonary TB is the early morn-ing gastric aspirate obtained in the hospital byusing a nasogastric tube before the child arisesand peristalsis empties the stomach of the respi-ratory secretions swallowed overnight (29,30).Three consecutive morning gastric aspirates yieldM. tuberculosis in only 30% to 50% of cases, al-though the yield from infants is as high as 70%(14). The culture yield from other body fluids ortissues from children with extrapulmonary TB isusually less than 50% (13). Gastric aspiration isinconvenient, expensive, and uncomfortable. Theculture yield from random, outpatient gastric as-pirates has not been determined recently. There-fore, this procedure cannot be recommended butshould be studied.

BronchoscopyThe role of bronchoscopy in evaluating children

for TB is controversial. The culture yield is lowerfrom bronchoscopy specimens than from properlyobtained gastric aspirates (29,31). Most childrendo not need flexible fiberoptic bronchoscopy, butthe procedure may be useful in diagnosing endo-bronchial TB and excluding other causes ofpulmonary abnormality, particularly in immuno-compromised children, such as those with HIVinfection in whom other opportunistic infectionsmay coexist with or mimic TB. In a recent studyof 36 children with pulmonary TB, bronchoscopyshowed endobronchial involvement in 42%; most(63%) of these children had no clinical or radio-graphic evidence of endobronchial TB (31). Thistechnique may be used to determine if a childmight benefit from corticosteroid therapy, butguidelines for making this decision have not beenestablished.

Clinical Scoring SystemTB is an enormous problem in developing coun-

tries, where about 95% of cases occur (6). Cost,technical difficulties, and lack of resources makeTB diagnosis in children very difficult in thesecountries. Various clinical scoring systems havebeen proposed on the basis of available informa-tion and tests (32,33) (Table 3). Although helpful,many of these systems have low sensitivity andspecificity. However, even in industrializedcountries, the triad of a positive tuberculin skintest, an abnormal radiograph, and a history ofexposure to an adult with TB remains the mosteffective method for diagnosing TB in children.

New Diagnostic Techniques

Polymerase Chain Reaction (PCR)Diagnostic PCR is a technique of DNA ampli-

fication that uses specific DNA sequences asmarkers for microorganisms (34). In theory, thistechnique can detect a single organism in a speci-men such as sputum, gastric aspirate, pleuralfluid, cerebrospinal fluid, or blood. Recent publi-cations show that various PCR techniques, mostusing the mycobacterial insertion element IS6110as the DNA marker for M. tuberculosis-complexorganisms, have a sensitivity and specificitygreater than 90% for detecting pulmonary TB inadults (35,36). However, these tests are not per-formed correctly in all clinical laboratories (36)

Table 3. A set of criteria for the diagnosis of pulmonarytuberculosis (TB) in children when culture is not available

A. Positive acid-fast stain of sputum or gastric aspirateor

B. Two or more of the following:• History of contact with a tuberculous adult• Cough lasting longer than 2 weeks• A reactive tuberculin skin test

≥ 10 mm in children without prior BCG vaccination≥ 15 mm in children with prior BCG vaccination

• Radiographic findings compatible with TB • Response to anti-TB therapy (increased

body weight by 10% after 2 months,decrease in symptoms)

Source: ref. 33.

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and may offer little advantage over high-qualitymicroscopic examination of sputum (34). The costinvolved and the need for sophisticated equip-ment and scrupulous technique to avoid cross-contamination of specimens preclude the use ofPCR techniques in many developing countries.PCR may have a special role in the diagnosis ofextrapulmonary TB and pulmonary TB in chil-dren since sputum smears are usually unreveal-ing in these cases.

Use of PCR for detecting M. tuberculosis inchildren has not been evaluated extensively.Pierre et al. (37) used an IS6110-based PCR todetect M. tuberculosis in gastric aspirate samplesfrom 22 children with pulmonary TB. They foundthat 15 (25%) of 59 samples were positive; how-ever, testing multiple samples or testing samplesat least twice improved the sensitivity. Whenthree samples from the same patient were testedtwo times each, two or more positive results wereobtained from 9 of 15 children with TB, but from0 of 17 controls. However, 2 of 65 single samplesfrom controls were positive by PCR. Using anIS6110-based PCR assay, Starke et al. (38) testedgastric aspirates from 35 hospitalized childrenwith pulmonary TB and 30 controls to detect M.tuberculosis. When compared with the clinicaldiagnosis, PCR had a sensitivity of 40% and speci-ficity of 80%. Six controls had false-positive PCRresults; one had a recent TB infection, two hadNTM disease, and three had conditions unrelatedto mycobacterial infection. Delacourt et al. (39)studied 199 specimens from 68 children with sus-pected TB. An IS6110-based PCR identified M.tuberculosis in clinical samples from 83% of chil-dren with disease compared to the low yield frompositive AFB smears (21%) and positive cultures(42%) (39). PCR identified 70% of children withclinical pulmonary TB but no other microbiologicproof of the infection. However, 39% of childrenwith infection but no radiographic or clinical dis-ease also had positive PCR results. These resultsagain demonstrate the arbitrariness of thedistinction between TB infection and disease inchildren.

It appears that PCR may have a useful butlimited place in evaluating children for TB. Anegative PCR result never eliminates TB as adiagnostic possibility, and a positive result doesnot confirm it. PCR’s major use will be in evalu-ating children with significant pulmonary dis-ease, when the diagnosis is not easily established

by clinical or epidemiologic grounds. PCR may beparticularly helpful in evaluating immunocom-promised children with pulmonary disease, al-though published reports of PCR performance insuch children are lacking. PCR may also aid inestablishing the diagnosis of extrapulmonary TB,though only rare case reports have been publish-ed. However, performing PCR on gastric aspiratesis not a useful test to distinguish between TBinfection and disease and should not be used forchildren with normal chest radiographs.

Serology and Antigen DetectionDespite dozens of studies published over the

past several decades, serology has found littleplace in the routine diagnosis of TB in adults orchildren. Several recent studies have used theenzyme-linked immunosorbent assay (ELISA) todetect antibodies to various purified or complexantigens of M. tuberculosis in children. Rosen (40)used mycobacterial sonicates in an ELISA onsamples from 31 children with clinical TB andfound a sensitivity of 26% and a specificity of 40%.This ELISA was influenced by recent BCG vacci-nation in children under 5 years of age. Barreraet al. (41) used an ELISA that detects antibodiesto purified protein derivative and found a sensi-tivity of 51% for culture-positive pulmonary TBcases in children, but the sensitivity was only 28%for the clinical cases. Hussey et al. (42) used anautoclaved suspension of M. tuberculosis to detectantibodies in serum from 132 children with clini-cal pulmonary TB; the test was 62% sensitive and98% specific. Higher sensitivity was obtainedamong patients with positive culture results(69%, n = 35), miliary TB (100%, n = 6), tuberculousmeningitis (80%, n = 15), and pleural effusion(78%, n = 16). No correlation was observed withthe tuberculin skin-test result, BCG vaccination,or nutritional status whereas duration of therapy,increasing age and chronicity of infection werepositively correlated. Delacourt et al. (43) used anELISA to detect IgG and IgM antibodies directedagainst mycobacterial antigen A60 in childrenwith TB. At a chosen specificity of 98%, IgG wasdetected in 68% of children with clinical diseasewhen results were highly controlled for age andprior BCG vaccination. IgM detection had only a19% sensitivity. However, using the same anti-A60 ELISA at a defined specificity of 95%,Turneer et al. (44) found the IgG sensitivity to be26% for past TB, 6% for asymptomatic primary

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TB, 14% for symptomatic TB, and 9% for NTMadenitis. No available serodiagnostic test for TBhas adequate sensitivity, specificity, or reproduci-bility under various clinical conditions to be use-ful for diagnosing TB in children.

Mycobacterial antigen detection has beenevaluated in clinical samples from adults, butrarely from children (45,46). Two recent assaysdetecting M. tuberculosis-specific antigensyielded high sensitivity and specificity in variousclinical specimens from adults with TB (47,48).Measurement of tuberculostearic acid, a myco-bacterial mycolic acid, has been used to detect M.tuberculosis in clinical specimens (49). Brooks etal. (50) demonstrated a sensitivity of 95% andspecificity of 91% when chromatographic profileof carboxylic acids and detection of tubercu-lostearic acid were combined and compared withculture results and clinical findings in adults withpulmonary TB; however, these techniques requiretechnically advanced equipment and expertise,which are not available where TB in children ismost common. Their sensitivity and specificity inchildren are unknown.

Implications for HIV Infection and Drug ResistanceThe resurgence of TB over the last decade has

coincided with the HIV pandemic. HIV-infectedinfants and children are in close contact withtheir caregivers, who may be infected with HIVand M. tuberculosis and are at high risk of devel-oping infectious TB as they become immunocom-promised. None of the available diagnostic testsfor TB infection or disease in children has beenevaluated systematically in children with HIVinfection and pulmonary disease or suspected TB.In adults with HIV infection and TB, the sensitiv-ity of diagnostic tests that rely on the host im-mune response, such as the TST or serology, ismuch lower than in nonimmunocompromised TBpatients. It is likely that the tests’ sensitivity alsowill be lower in HIV-infected children with TB.Tests that directly detect M. tuberculosis, such asPCR or antigen detection assays, may be particu-larly important for HIV-infected children. Theculture yield of M. tuberculosis from children withHIV infection and TB is unknown but appears tobe similar to that from non-HIV-infected children.The most important diagnostic clue for detectingTB in HIV-infected children is a history of contactwith an adult who has infectious TB. Since TBmay not have yet been diagnosed in this adult, a

rapid and aggressive evaluation for TB in adultswho care for the child is a critical part of theevaluation of the child.

The current prevalence of drug resistanceamong M. tuberculosis isolates in the UnitedStates is 8% to 14% (51, 52). Drug resistance ismost common in patients who received treat-ment, are not responding to therapy, do not ad-here to treatment, live in developing countries,are immunocompromised, are prisoners, arehomeless, or are children exposed to adults atincreased risk for drug resistance. Drug-resistantTB has increased significantly among children(52). Because of low culture yields from childrenwith TB, the clinician must often rely on theantimicrobial susceptibility results for the M. tu-berculosis isolate obtained from the adult sourcecase who presumably infected the child. Thisagain emphasizes the crucial need to identify andevaluate the source case for every child with TB.The rapid identification of drug-resistant organ-isms is necessary for control of drug-resistant TB.Various new methods, such as high-performanceliquid chromatography or PCR and DNA se-quence analysis, may help to identify and test forantimicrobial susceptibility within a few days ofdiagnosis, but these techniques remain experi-mental.

SummaryMost recently developed sensitive and specific

diagnostic tests have not found a place in theroutine evaluation of children with suspected TB.Clinical criteria, particularly skin-test results,radiographic changes, and documented exposureto an infectious adult remain standard diagnosticmethods. In industrialized countries, the localpublic health entity is a crucial partner to theclinician in establishing the diagnosis in the childand determining if drug resistance is present. Asnew diagnostic tests are developed, they must beevaluated against clinical criteria. The basic dif-ferences in pathophysiology of TB in adults andchildren must be considered before new tests areapplied in pediatrics. It will be crucial to study thenew techniques in children and not simply ex-trapolate from results for adults with TB.

Dr. Khan is a postgraduate fellow in pediatricinfectious diseases at Baylor College of Medicine,Houston, Texas. Dr. Starke is an associate professor atBaylor College of Medicine and current chairman of

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CDC’s Advisory Committee for the Elimination ofTuberculosis.

References 1. Starke JR, Correa AG. Management of mycobacterial

infection and disease in children. Pediatr Infect Dis J1995;14:455-70.

2. Styblo K, Rouillon A. Tuberculosis in developing coun-tries: burden, intervention and cost. Bull Int UnionAgainst Tuber Lung Dis 1990;65:6-24.

3. Starke JR, Jacobs R, Jereb J. Resurgence of tubercu-losis in children. J Pediatr 1992;120:839-55.

4. Cantwell M, Snider D Jr, Cauthen G, Onorato I.Epidemiology of tuberculosis in the United States,1985 through 1992. JAMA 1994;272:535-9.

5. Kochi A. The global tuberculosis situation and thenew control strategy of the World Health Organiza-tion. Tuber Lung Dis 1991;72:1-6.

6. Raviglione MC, Snider DE, Kochi A. Global epidemiol-ogy of tuberculosis. Morbidity and mortality of aworldwide epidemic. JAMA 1995;273:220-6.

7. Dolin P, Raviglione M, Kochi A. Global tuberculosisincidence and mortality during 1990-2000. Bull WorldHealth Organ 1994;72:213-20.

8. Barnes, PF Borrows, SA. Tuberculosis in the 1990s.Ann Intern Med 1993;119:400-10.

9. Hsu KHK. Contact investigation: a practical ap-proach to tuberculosis eradication. Am J PublicHealth 1963;53:1761-9.

10. Nolan RJ Jr. Childhood tuberculosis in North Caro-lina: a study of the opportunities for intervention inthe transmission of tuberculosis to children. Am JPublic Health 1986;76:26-30.

11. Brailey ME. Tuberculosis in white and negro children.II. The epidemiologic aspects of the Harriet Lanestudy. Cambridge, MA: Harvard University Press,1958.

12. Steiner P, Rao M, Victoria MS, et al. Persistentlynegative tuberculin reactions: their presence amongchildren culture positive for M. tuberculosis. Am J DisChild 1980;134:747-50.

13. Starke JR, Taylor-Watts KT. Tuberculosis in the pedi-atric population of Houston, Texas. Pediatrics1989;84:28-35.

14. Vallejo J, Ong LT, Starke JR. Clinical features, diag-nosis and treatment of tuberculosis in infants. Pedi-atrics 1994;94:1-7.

15. Lifschitz M. The value of the tuberculin skin test as ascreening test for tuberculosis among BCG-vacci-nated children. Pediatrics 1965;36:624-7.

16. Landi S, Ashley MJ, Grzybowski S. Tuberculin sensi-tivity following the intradermal and puncture meth-ods of BCG vaccination. Can Med Assoc J1967;97:222-5.

17. Joncas JH, Robitaille R, Gauthier T. Interpretation ofthe PPD skin test in BCG-vaccinated children. CanMed Assoc J 1975;113:127-8.

18. Johnson H, Lee B, Kelly E, McDonnell T. Tuberculinsensitivity and the BCG scar in tuberculosis contacts.Tuber Lung Dis 1995;35:113-7.

19. Menzies R, Vissandjee B. Effect of bacille Calmette-Guerin vaccination on tuberculin reactivity. Am RevRespir Dis 1992;141:621-5.

20. Sepulveda RL, Burr C, Ferrer X, Sorensen RU.Booster effect of tuberculin testing in healthy 6-year-old school children vaccinated with bacille Calmette-Guerin at birth in Santiago, Chile. Pediatr Infect DisJ 1988;7:578-82.

21. American Thoracic Society. Diagnostic standards andclassification of tuberculosis. Am Rev Respir Dis1990;142:725-35.

22. American Academy of Pediatrics Committee on Infec-tious Diseases. Screening for tuberculosis in infantsand children. Pediatrics 1994;93:131-4.

23. Schaaf HS, Beyers N, Gie RP, et al. Respiratory tuber-culosis in childhood: the diagnostic value of clinicalfeatures and special investigations. Pediatr Infect DisJ 1995;14:189-94.

24. Parisi MT, Jensen MC, Wood BP. Pictorial review ofthe usual and unusual roentgen manifestations ofchildhood tuberculosis. Clin Imag 1994;18:149-54.

25. Delacourt C, Mani TM, Bonnerot V, et al. Computedtomography with normal chest radiograph in tuber-culous infection. Arch Dis Child 1993;69:430-2.

26. Strumpf IJ, Tsang AY, Syre JW. Reevaluation of spu-tum staining for the diagnosis of pulmonary tubercu-losis. Am Rev Respir Dis 1979;119:599-602.

27. Lipsky BA, Bates J, Tenover FC, Plorde JJ. Factorsaffecting the clinical value of microscopy for acid-fastbacilli. Rev Infect Dis 1984;6:214-22.

28. Kent PT, Kubica GP. Public health mycobacteriology– a guide for the level III laboratory. Atlanta, GA;Centers for Disease Control, 1985.

29. Abadco DL, Steiner P. Gastric lavage is better thanbronchioalveolar lavage for isolation of Mycobac-terium tuberculosis in childhood tuberculosis. PediatrInfect Dis J 1992;11:735-8.

30. Carr DT, Karlson AG, Stillwell AA. A comparison ofcultures of induced sputum and gastric washings inthe diagnosis of tuberculosis. Mayo Clinic Proc1967;42:23-5.

31. Chan S, Abadco DL, Steiner P. Role of flexible fiberop-tic bronchoscopy in the diagnosis of childhood endo-bronchial tuberculosis. Pediatr Infect Dis J1994;13:506-9.

32. Glidey Y, Hable D. Tuberculosis in childhood: ananalysis of 412 cases. Ethiop Med J 1983;21:161-7.

33. Migliori AB, Borghesi A, Rossanigo P et al. Proposalfor an improved score method for the diagnosis ofpulmonary tuberculosis in childhood in developingcountries. Tuber Lung Dis 1992;73:145-9.

34. Schluger NW, Rom WN. Current approaches to thediagnosis of active pulmonary tuberculosis. Am JRespir Crit Care Med 1994;149:264-7.

35. Eisenach KD, Sifford MD, Cane MD, Bates JH, Craw-ford JT. Detection of Mycobacterium tuberculosis insputum samples using a polymerase chain reaction.Am Rev Respir Dis 1991;144:1160-3.

36. Noordhock A, Kolk A, Bjune G, et al. Sensitivity andspecificity of polymerase chain reaction for detectionof Mycobacterium tuberculosis: a blind comparisonstudy among seven laboratories. J Clin Microbiol1994;32:277-84.

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37. Pierre C, Oliver C, Lecossier D, Bousssougant Y, YemiP, Hance AJ. Diagnosis of primary tuberculosis inchildren by amplification and detection of mycobacte-rial DNA. Am Rev Respir Dis 1993;147:420-4.

38. Starke JR, Ong LT, Eisenach KD, et al. Detection ofM. tuberculosis in gastric aspirate samples from chil-dren using polymerase chain reaction. Am Rev RespDis 1993;147(Suppl):A801.

39. Delacourt C, Poveda J-D, Churean C, et al. Use ofpolymerase chain reaction for improved diagnosis oftuberculosis in children. J Pediatr 1995;126:703-9.

40. Rosen EU. The diagnostic value of an enzyme-linkedimmunosorbent assay using adsorbed mycobacterialsonicates in children. Tubercle 1990;71:127-30.

41. Barrera L, Miceli I, Ritacco V, et al. Detection ofcirculating antibodies to purified protein derivativeby enzyme-linked immunosorbent assay: its potentialfor the rapid diagnosis of tuberculosis. Pediatr InfectDis J 1989;8:763-7.

42. Hussey G, Kibel M, Dempster W. The serodiagnosisof tuberculosis in children: an evaluation of an ELISAtest using IgG antibodies to M. tuberculosis, strainH37RV. Ann Trop Paediatr 1991;11:113-8.

43. Delacourt C, Gobin J, Gaillard J-L, de Blic J, VeranM, Scheinmann P. Value of ELISA using antigen 60for the diagnosis of tuberculosis in children. Chest1993;104:393-8.

44. Turneer M, Nerom EV, Nyabenda J, Waelbroeck A,Duvivier A, Toppet M. Determination of humoral im-munoglobulins M and G directed against mycobacte-rial antigen 60 failed to diagnose primary tuberculosisand mycobacterial adenitis in children. Am J RespirCrit Care Med 1994;150:1508-12.

45. Sada E, Ruiz-Palacios AM, Lopez-Vidal Y, et al. Detec-tion of mycobacterial antigens in cerebrospinal fluidof patients with tuberculous meningitis by enzyme-linked immunosorbent assay. Lancet 1983;2:651-2.

46. Radhakrishnan VV, Sehgal S, Mathai A. Correlationbetween culture of Mycobacterium tuberculosis anddetection of mycobacterial antigens in cerebrospinalfluid of patients with tuberculous meningitis. J MedMicrobiol 1990;33:223-6.

47. Wadee AA, Boling L, Reddy SG. Antigen capture assayfor detection of a 43-kilodalton Mycobacterium tuber-culosis antigen. J Clin Microbiol 1990;28:2786-91.

48. Sada E, Aguilar D, Torres M, et al. Detection oflipoarabinomannan as a diagnostic test for tuberculo-sis. J Clin Microbiol 1992;30:2415-18.

49. Brooks JB, Daneshvar MI, Fast DM, et al. Selectiveprocedures for detecting femtomole quantities of tu-berculostearic acid in serum and cerebrospinal fluidby frequency-pulsed electron-capture gas-liquid chro-matograph. J Clin Microbiol 1987;25:1201-6.

50. Brooks JB, Daneshvar MI, Harberger RL, et al. Rapiddiagnosis of tuberculous meningitis by frequency-pulsed electron-captive gas-liquid chromatographydetection of carboxylic acids in cerebrospinal fluid. JClin Microbiol 1990;28:989-97.

51. Centers for Disease Control and Prevention. Nationalaction plan to combat multidrug-resistant tuberculo-sis. MMWR 1992;41:5-50.

52. Bloch AB, Cauthen GM, Onorato IM, et al. Nation-wide survey of drug-resistant tuberculosis in theUnited States. JAMA 1994;271:665-71.

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Data Management Issues for Emerging Diseases and NewTools for Managing Surveillance and Laboratory Data

Stanley M. Martin, M.S., Nancy H. Bean, Ph.D.Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Data Management Issues for Emerging DiseasesSince 1976, when Legionnaires’ disease af-

fected attendees at the American Legion Conven-tion in Philadelphia (1), the scope of public healthhas expanded. During the 1976 outbreak investi-gation, public attention was drawn to news ac-counts of the increasing numbers of cases anddeaths as well as to speculations about diseasescauses and prevention. After the outbreak, publichealth officials contended with volumes of infor-mation, including clinical data, epidemiologicsurvey results, and records of specimens collectedfrom patients and the environment. This informa-tion was managed on mainframe computers.

In 1980, a cluster of cases of unrecognizedillness, primarily affecting young women, createda data management situation similar to that sur-rounding the Legionnaires’ disease outbreak. Amajor epidemiologic investigation, which includedexamining a multitude of laboratory specimensand analyzing volumes of data, was undertakenby a large team of federal, state, and local publichealth officials, as well as numerous academicinstitutions and private industries. The problemswith establishing databases and implementing adata management system for toxic shock syn-drome (2) were essentially the same as the datamanagement problems of Legionnaires’ disease,except that computer technology had crept for-ward slightly in public health offices.

During the spring of 1993, a cluster of cases ofanother unknown illness, eventually attributedto hantavirus (3), occurred in the southwesternUnited States. The reaction to this unknown dis-ease by public health officials reflected a startlingfact: even though the epidemiologic and labora-tory methods for curtailing the outbreak were inplace, a consistent data management strategyhad not been established. Ad hoc databases builtby outbreak investigators for a multitude of pur-poses began to bog down the investigation. Caseswere recorded in multiple databases that did notrecognize duplicate reports of cases. Updates ofdata about cases were done in some, but not all,databases. Laboratory data about specimens

from patients were not linked to other clinical andepidemiologic data about a patient. No singledatabase was available with well-edited, com-plete data about all the cases. Parallel, frag-mented data management efforts evolved in atleast 15 locations, with no coordinated mecha-nism to integrate them into one system.

Introducing a single system for data manage-ment in the midst of the hantavirus outbreakinvolved more than the data management issuesencountered in the earlier outbreaks. Previously,computer technology was viewed as a solutionthat, although somewhat cumbersome, enabledofficials to move from data management by handto electronic management. However, during thehantavirus outbreak, computer technology be-came part of the problem; it initially preventedgood data management and may have hinderedsome of the laboratory and epidemiologic effortsto control the outbreak. Data were essentiallybeing locked into various databases and could notbe adequately analyzed or merged with data inother databases. In some instances, this peculiarcircumstance caused investigators to performanalyses by hand using printouts from electronicdatabases or entering data again into other sys-tems.

In recent years, legal considerations, such asthe Privacy Act enacted in 1974 and the Freedomof Information Act enacted in 1966 (4,5), have alsocomplicated data management. These acts, intheir efforts to protect individual privacy andensure availability of data, have in some cases,constrained public health responses to emergencysituations and subsequent surveillance efforts byenforcing strict database design and handlingrequirements.

Data Management RequirementsIn epidemiologic investigations, disease prob-

lems are generally characterized by person, place,and time, whether the problem concerns theemergence of a new disease, a change in theresistance pattern of a known pathogen, an emer-gency response to an outbreak, or a routine

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disease surveillance program. The principles ofdata gathering, management, and analysis areessentially the same for all these purposes. Com-puter systems developed to manage data associ-ated with these problems should be regarded astools for the epidemiologic characterization ofpathogens, syndromes, cases, and risk factors.Therefore, laboratory data management and re-porting systems must be able to handle dataabout all of these.

The most stringent requirements for datamanagement are imposed by data from labora-tory testing of specimens from patients, humanand nonhuman sources, and the environment. Asystem having a relational data model adequateto properly handle the laboratory data require-ments will almost certainly be adequate to handlethe clinical, exposure, and demographic data re-quirements.

Two primary data management functions cansatisfy the laboratory data demands with multi-ple requirements in each function. The first func-tion, internal laboratory data management,consists of entering test results and trackingspecimens. The second, surveillance, includesgathering data and moving data beyond the elec-tronic files of the laboratory to appropriate sitesfor analysis. A data management system shouldbe able to perform these functions not only duringan outbreak but throughout the period of surveil-lance as well.

The internal laboratory function, universallysimilar among most public health laboratories,includes data entry tailored for individual labora-tories at the site; retrieval/query ability; and abil-ity to add or delete tests, manage aliquots, sharedata input in different laboratories of the site,track the status of every specimen regardless ofwhich laboratory tested it, develop reports forspecimen submitters, and in some cases assigncosts for laboratory tests performed and prepareinvoices for submitters.

Requirements for the surveillance function in-clude, in addition to certain critical laboratorydata, the following facilities: to record clinical,exposure/risk factor, and demographic data aboutpatients; to include data about multiple speci-mens and aliquots related to the same person,regardless of the interval separating thespecimen dates; and to change questions or testresults that are recorded for each specimen.

Although internal and surveillance functionsare clearly separate, they are not independent.Data entered into databases for the internal func-tion should be available without additional effortfor the surveillance function. In fact, when theinternal function is not electronic or when theinternal electronic system is inadequate, the sys-tem performing electronic surveillance shouldalso perform to some extent the internal func-tions. Good laboratory data management does notaddress the internal function at the exclusion ofthe surveillance function.

If a laboratory data management system is tobe useful for emergency situations, it must pro-vide mechanisms for adapting quickly to theemergency situation. For example, it must pro-vide a way to immediately create an electronicdata collection instrument and to incorporate thisnew instrument into the system at all reportingsites electronically. For the surveillance function,these electronic features must include communi-cations facilities to move data electronically fromone location to another, mechanisms for sendingmessages or files, functions for simple analysis,and methods for preparing and printing reports.While some systems perform some of these func-tions, most systems do not provide all of them.

With appropriate systems in hand, data man-agement plans for both urgent and routine eventscan be approached in a sequential fashion. Withconsensus among all participating investigators,epidemiologists must decide what data (bothlaboratory and epidemiologic) are needed so thatdata field characteristics can be defined. Consen-sus should be reached in the early phase of theoutbreak investigation; otherwise participants inthe investigation will of necessity begin develop-ing ad hoc data management systems. The morethoroughly and carefully this task is performed,the more stable the data will ultimately become.

In a well-designed system, the initial defini-tions in an emergency situation can include pro-jections about which data fields will be needed.However, for routine surveillance these can bemore thoroughly planned. Thus, the data systemshould allow fields to be deleted if not needed andto be added if they become important. Thesemodifications should 1) be handled without hav-ing to alter the system, 2) use simple menu-drivenfunctions requiring no computer programmerintervention, 3) accomplish the changes

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immediately, 4) be distributed to all investigatorswithout disrupting their other functions duringthe investigation, and 5) be incorporated auto-matically.

Next, all known participants in the investiga-tion must be identified. These should includelocal, state, and federal officials as well as aca-demic or private participants who may providereports to the central data repository. These par-ticipants must be identified to the system specifi-cally by person and by site for system security.Appropriate state and federal offices should beinformed concerning the computer system andthe rules for its use well before an emergencyoccurs; therefore, sites will be on the system inadvance of an urgent problem. However, the sys-tem must allow for additional sites to be addedquickly. In an emergency, a temporary agreementmust be drawn for all participants to cooperatewith the demands of the situation, i.e., to use aparticular software system and operate under astandard set of rules for collecting and reportingdata for the emergency. This agreement may oc-casionally stipulate that participants share datatemporarily in a common database for the sake ofdata integrity.

Entering clinical, epidemiologic/risk factor,and laboratory data about the same cases into thesame database, rather than merging separatedatabases after the data are collected, providessuch great payoffs in time savings and data integ-rity that the effort to obtain cooperation for acommon database during an urgent situation isworthwhile. Although merging multiple data-bases during routine surveillance is feasible,emergency situations do not lend themselves tothis type of data management. Therefore, thesystem to be used for these situations must ac-commodate a common database and provide ameans of connecting the reporting sites to thedatabase. When the reporting system is activatedand data begin arriving at a central location, thesystem should facilitate analysis at every report-ing site and provide a mechanism to export data(e.g., ASCII or .dbf files) for external analysis.

Emergency situations create unusual de-mands for epidemiologic and laboratory re-sources; therefore, data management should notdisrupt or threaten to divert resources devoted tothese other purposes. As the system is imple-mented, before emergencies occur, discussions ofthe resources required should be held with

participants. Participants must devote some re-sources to data management, but these should beminimized. This is consistent with implementinga single system in the beginning of the outbreakinvestigation and continuing with it into the rou-tine surveillance follow-up. Incorporating datainto a second system for surveillance could wasteresources.

Although, internal data management does notneed to change to accommodate an outbreak,laboratories must implement systems that candirectly feed data into the master reporting sys-tem database, either through an import functioncontained in the master system or by a directinterface between the internal laboratory systemand the surveillance reporting system.

Data management considerations during out-break investigations and surveillance in theUnited States include the political concerns of theparticipants. Political and legal constraints of allparticipants must be addressed before the needto deal with them arises. On a global scale, thisconsideration is equally important, especially incountries whose economies may be adversely af-fected by news of a dangerous disease situation.Individual country sovereignty must not be vio-lated by data reporting, and the cooperation ofeach participating country or political entity (e.g.,World Health Organization [WHO], Pan Ameri-can Health Organization [PAHO]) must be ob-tained in an atmosphere of confidentiality. Allattempts to obtain, share, or combine data on aregional or global basis must include a well-de-fined set of rules agreed upon by all participants.For example, data for scientific purposes might bereceived at an office of WHO or PAHO but notsent beyond these organizations.

Most often, for the sake of surveillance on aregional or global scale, data management consid-erations must focus first on establishing in-coun-try data management infrastructures. Thismeans that regional or global surveillance willfirst translate into establishing a master system,or at least compatible systems in individual par-ticipating countries. In most cases, data manage-ment systems available to developing countriesdo not provide the relational model needed by thelaboratory. Therefore, efforts should be initiatedto introduce and establish systems that can meetthese needs in countries desiring to use them.

A plan for regional or global surveillance mustinclude tools to respond to outbreaks and provide

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for the computing equipment and modems orother means of transmitting the data electroni-cally. Today’s environment demands that mostdata management be done on personal computerslocated at critical sites where data can be input.However, data volume may ultimately requirethat the system provide for archiving data ontoanother medium. This does not preclude the useof personal computers for data management butsimply recognizes that current technology limitsthe volume of data that can practically be man-aged and analyzed on personal computers.

The initial data management plan for a coun-try should include a section on reporting proce-dures and the appropriate medium for archivingdata. To handle an immediate, urgent situationthe system should contain, at a minimum, a per-sonal computer with large hard-disk capacity (atleast 1-2 gigabytes at the central level and possi-bly 300-500 megabytes at each reporting site),large memory (at least 4 megabytes of RAM atevery reporting site), adequate speed (at least 33megahertz at every reporting site), and fast mo-dems if appropriate. For sites located in areaswith inadequate telephone lines, other provisionsfor electronic transmissions should be planned(e.g., diskettes). Until security can be assured onthe Internet, we do not recommend using thismedium for electronic transmission of laboratoryclinical data for outbreak investigations and sur-veillance.

New Tools for the Management of Surveillance andLaboratory Data

The Public Health Laboratory Information System(PHLIS)To address the need for a data management

system for outbreak investigations and surveil-lance, the National Center for Infectious Dis-eases, CDC, in cooperation with the Associationof State and Territorial Public Health LaboratoryDirectors in the United States, developed PHLIS.With this system, data entry screens (modules)are created and distributed to all reporting siteselectronically, and data are input and reportedwithin hours, without involving computer pro-grammers. PHLIS provides the capacity for ahierarchical reporting scheme involving reportsto multiple, successively higher reporting levels;a database is created at every reporting level so

that all data reported to a site or input at the siteare included in the database at that site.

The most recent version of PHLIS (Version3.0), is a menu-driven system based on a rela-tional data model sufficient for the needs outlinedin the first part of this report. The system allowsfor a patient record to be input only one time andlinks multiple specimens for that patient record.This is true even if specimens for the same patientare entered in different disease modules, or if thepatient’s name is to be added into a module thatcontains only epidemiologic data (no laboratoryspecimens). PHLIS provides a core set of data tobe collected on every patient. In addition, eachdisease module can be customized by adding ad-ditional fields to the core data if needed. Thesystem can accommodate data for epidemiologic,laboratory, survey, and case-control studies, andfor other public health needs.

Field staff can rapidly add their own data fieldsto existing disease modules to customize the dataentry for special needs at each data reporting site.During an outbreak, a new module can be rapidlydeveloped and electronically transmitted to allparticipating reporting sites.

The system, which includes data communica-tion software, is configured so that data flow in apyramid reporting structure: that is, data arereported from lower level reporting sites throughhigher level reporting sites and ultimately to asingle central site. As data are passed to eachsuccessively higher level, they are automaticallyassimilated into that site’s database. Thus, data-bases are built and updated at successivelyhigher reporting sites. Additional informationabout a case or specimen may be added at anyreporting site; if desired, these additional dataare also transmitted to the next higher reportingsite.

To meet the need for feedback, PHLIS has amenu-driven option to transmit files or messagesup and down the reporting chain, with these filesand messages being transmitted automaticallywhen connections are established for each datatransmission. This facility is flexible enough toallow any valid user in the reporting chain totransmit files or messages to any other user in thereporting chain. For example, in the UnitedStates, a county health official who is included inthe reporting system in one state can send mes-sages or files to a participating county official in

Synopses


another state. The feedback system does notmimic electronic mail because these files andmessages are sent along the reporting chain inthe same communications configuration as datareporting. Therefore, successful arrival of thesemessages at their destination(s) depends uponeach member of the reporting chain between thesender and the receiver to establish a connectionfor reporting purposes. However, the system pro-vides an alternative mechanism for sending filesand messages directly to any other reporter hav-ing the capacity to receive them without goingthrough the reporting chain.

PHLIS is used in all 50 state public healthlaboratories, as well as the District of Columbiaand Guam. Disease modules included are animalrabies, Campylobacter, Escherichia coli O157:H7,Lyme disease, mycobacteria, respiratory and en-teric viruses, human Salmonella, nonhuman Sal-monella, Shigella, and drug-resistant Strepto-coccus pneumoniae.

PHLIS can be implemented independently: or-ganizations can develop their own PHLIS pyra-mid reporting system. For example, PHLIS iscurrently being implemented at the CaribbeanEpidemiology Center (CAREC) in Trinidad and inits member countries for the reporting ofHIV/STD infections with the expectation that thereporting system will be expanded to accommo-date other diseases. CAREC can receive reportsfrom the member countries as each country isadded to the reporting structure.

Laboratory Information Tracking System (LITS)The second system, LITS, is a PC local area

network-based system for tracking laboratoryspecimens. The system allows specimen informa-tion to be entered at a central specimen receivingsite; additional information about the specimencan be entered into the system in any of the

laboratories performing tests on that specimen.Although modules are customized for each labo-ratory’s needs, laboratorians can add additionaltests or delete obsolete ones. Furthermore, userscan examine all the data about a specimen, in-cluding data from all laboratories that performedtests on the specimen. Other features in the sys-tem include cost billing, user defined reports, userdefined query, and specimen or patient trackingand security. For emerging diseases, LITS pro-vides a mechanism to standardize laboratory pro-tocol across organizations and a mechanism toshare data about specimens within an organiza-tion.

AcknowledgmentsWe thank Tim Kuhn for leading the programming team;Bruce Wilson, Dana Crenshaw, Joe Bates, and Neil Jones forprogramming support; Tim Day for user support; KathleenMaloney, Joy Goulding, Lori Hutwagner, and Cecile Ivey forevaluating program integrity; Brian Plikaytis for his earlyinvolvement with LITS; and Cheryl Shapiro for financialmanagement.

References1. Fraser DW, Tsai TR, Orenstein W, Parkin WE,

Beecham HJ, Sharrar RG. Legionnaires’ disease: de-scription of an epidemic of pneumonia. N Engl J Med1977;297:1189-97.

2. Shands KN, Schlech WF III, Hargrett NT, Dan BB,Schmid GP, Bennett JV. Toxic shock syndrome: case-control studies at the Centers for Disease Control.Ann Intern Med 1982;96:895-8.

3. CDC. Outbreak of acute illness—southwesternUnited States, 1993. MMWR 1993;42:421-4.

4. Administrative Conference of the U.S. Privacy Act. In:Federal Administrative Procedure Sourcebook, 2nded. Office of the Chairman, 1992:863-979.

5. Administrative Conference of the U.S. Freedom ofInformation Act. In: Federal Administrative Proce-dure Sourcebook, 2nd ed. Office of the Chairman,1992:633-61.

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Helicobacter hepaticus, a Recently Recognized BacterialPathogen, Associated with Chronic Hepatitis and

Hepatocellular Neoplasia in Laboratory MiceGastric carcinoma, one of the most prevalent

human cancers worldwide, is among the neo-plasms for which epidemiologic evidence of envi-ronmental causes is strongest. The exact natureof these environmental causes was obscure untilmounting evidence recently linked chronic infec-tion of the gastric antrum mucosa by Helicobacterpylori (a microaerobic, gram-negative, spiral bac-terium) with elevated cancer risk (1). It is nowrecognized that gastric B-cell lymphoma of mu-cosa-associated lymphoid tissue is also closelylinked to gastric H. pylori infection, and eradica-tion of the infection with antibiotics can result inregression of the lymphoma (2,3). This startlingfinding has stimulated intense interest in the ge-nus Helicobacter and related organisms; as a re-sult, additional species of Helicobacter are nowfrequently isolated and characterized from manynon-human hosts. Until 1994, however, only H.pylori was known to be associated with tumordevelopment, in humans or in any other animalspecies.

In 1992, at the National Cancer Institute’sFrederick Cancer Research and DevelopmentCenter (FCRDC) in Frederick, Maryland, a highprevalence of liver disease was observed amongcertain strains of mice; these mice were untreatedcontrols in long-term chemical carcinogenesis ex-periments. Affected strains, notably A/JCr, hadbeen bred at FCRDC under pathogen-free condi-tions and were free of known serologically detect-able murine viruses and parasites; moreover, theyhad no histologically demonstrable hepatic abnor-malities, except for a very low incidence (1% to 2%)of hepatocellular tumors in mice 15 months of ageor older. Over a very short period, the prevalenceof a histologically distinctive form of hepatitisincreased to virtually 100% in male mice at 1 yearof age (Table 1). The earliest demonstrable lesionswere small, undistinctive foci of hepatic necrosisseen in young mice aged 2 to 6 months. In oldermice, aged 6 to 10 months, there was a highlydistinctive pericholangitis, consisting of abundantmononuclear cell infiltrates around bile ductswithin portal triads. The biliary epithelium withinaffected ducts was focally swollen, and the luminal

surfaces of damaged epithelial cells were poorlydefined in hematoxylin and eosin-stained sections(4,5). In livers with extensive lesions, bile ductular(oval cell) hyperplasia was also prominent. More-over, mice with hepatitis usually had hepatocellu-lar tumors, often multiple, that included bothadenomas and carcinomas (4).

Hepatocellular tumors in mice are one of themost common endpoints in bioassays for chemicalcarcinogens. They were not, at that time, knownto be associated with infectious agents. Accord-ingly, initial efforts to identify the cause of thehepatitis/hepatocellular tumor syndrome were di-rected toward possible sources of chemical expo-sure. The possibility of accidental exposure toexperimental substances within the research ani-mal facilities was ruled out when liver disease wasidentified in mice that had never left the breedingareas which are located in separate buildings.Extensive chemical analyses of food, bedding,water, and other possible sources of toxic sub-stances had negative results.

Detailed pathologic examination by light mi-croscopy of tissue sections from diseased liverswas continued, and many special stains wereused. One such stain, Steiner’s silver impregna-tion procedure for spirochetes (6), revealed in he-patic tissue uniform bodies that were consistentin size and shape with bacteria. Homogenates offresh liver tissue from diseased mice proved effec-tive in transmitting hepatitis to A/J mice pur-chased from commercial sources outside FCRDC,when given by intraperitoneal injection (5). Inaddition, from these homogenates, a motile, spiralbacterium could be cultivated on blood agar platesincubated at 37o C under anaerobic or microaero-bic conditions.

This organism was subsequently characterizedby ultrastructural morphologic examination, bio-chemical characteristics, and 16S rRNA gene se-quence. Determined to be a new species related toH. pylori, it was given the name H. hepaticus (7).The bacterium is motile and gram negative, 0.2 to0.3 µm in diameter, 1.5 to 5.0 µm long, and curvedto spiral in shape, with one to several spirals; ithas bipolar sheathed flagella (one at each end) but

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lacks the periplasmic fibers that envelope the bac-terial cells in other mouse Helicobacter species. H.hepaticus has strong urease activity, is oxidaseand catalase positive, produces H2S, reduces ni-trate to nitrite, and grows microaerobically at 37o

C but not at 25o C or 42o C. It is resistant tocephalothin and nalidixic acid but sensitive tometronidazole. Photographs illustrating its mor-phologic structure by light (4,5) and electron(4,5,7) microscopy have been published. The spe-cies-defining characteristic of the organism, thenucleotide sequence of its 16S rRNA gene, hasbeen used to develop a diagnostic assay based onpolymerase chain reaction (8).

Systematic examination of rodents of all spe-cies and strains produced at FCRDC, especiallyretired breeders, showed that the characteristichepatitis and associated bacteria were present inmice of several strains (A/JCr, DBA/2NCr,C3H/HeNCr) and that within these strains, themale mice were more severely affected than thefemale. Mice with severe combined immunodefi-ciencies were especially vulnerable. The preciselocation of organisms demonstrable by Steinerstain within infected liver parenchyma was shownby transmission electron microscopy to be invari-ably extracellular and characteristically withinbile canaliculi (4,5). No liver disease was seen insome strains (e.g., C57BL/6NCr) or in F1 hybridsbetween sensitive and resistant strains (e.g.,B6C3F1). Rodent species other than mice (e.g.,rats, Syrian hamsters, and guinea pigs) were notaffected.

In infected mice with severe combined immu-nodeficiency, cecal inflammation was histologi-cally demonstrable (5), and organisms wereisolated from the mucosa of the large intestine (7),which may mean that the usual ecologic nicheoccupied by H. hepaticus is that of a commensal

colonizer of the intestinal tract (8). Since mice arecoprophagic, it appears highly likely that naturaltransmission of the organisms is the oral-fecalroute. Why and how H. hepaticus invades the liverin mice of certain strains remain to be determined.Hepatitis is also characteristic of certain otherenteric pathogenic bacteria, such as Campylobac-ter jejuni (9) that, unlike H. hepaticus, have notbeen associated with liver tumor development.The tissue damage that accompanies persistentinfection by H. hepaticus, H. pylori, and certainother Helicobacter species may be due, at least inpart, to a soluble, trypsin-sensitive cytotoxin ofhigh molecular weight produced by these organ-isms (10). There is no precedent for any direct roleof such a toxin in carcinogenesis. On the otherhand, chronic infections by viruses, bacteria, orcertain parasites are recognized risk factors forhuman cancers at various sites. The hypothesisthat chemically reactive, potentially genotoxic,substances of low molecular weight (including ni-tric oxide and active oxygen species) generated byinflammatory cells at the site of chronic infectionmay initiate or enhance carcinogenesis has beenexamined (11). The hypothesis is under activeinvestigation in the context of H. hepaticus-asso-ciated liver disease.

H. hepaticus is susceptible to a number of anti-biotics; treatment of susceptible, naturally in-fected 8- to 10-week-old strain A/JCr mice withsingle or combined antimicrobial agents has beenevaluated for efficacy in eradicating establishedinfections (12). Amoxicillin, metronidazole, andtetracycline administered singly failed to eradi-cate bacteria from the gastrointestinal tract, buteither amoxicillin or tetracycline, in combinationwith metronidazole and bismuth, was effective ineradicating H. hepaticus from the liver, cecum,and colon when given by oral gavage for a period

Table 1. Increasing prevalence of hepatitis and hepatocellular neoplasia in control male A/JCr mice at the National Cancer Insti-tute’s Frederick Cancer Research and Development Center, 1989-1992a

Number Age, Mice with Mice withDate killed of mice in weeks hepatitis (%) liver tumors (%)

Jan-Mar 1989 48 47±3 0 0May-Jul 1989 47 70±60 0 1 (2)Jan-Apr 1992 6 36±4 2 (33) 0Jul 1992 16 54 16 (100) 1 (6)Aug-Oct 1992 6 64±3 5 (83) 3 (50)Dec 1992 12 77 12 (100) 11 (92) aAdapted from ref. 4.

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of 2 weeks (12). The effect of antibiotic therapy onthe carcinogenic process, or in older animals, re-mains to be established.

The importance of H. hepaticus to humans isnot yet completely known. The organism clearlyhas the potential to confound bioassays for chemi-cal carcinogens, but this potential has no directeffect on humans. Even though most Helicobacterspecies identified to date are characteristicallyassociated with (and named after) specific mam-malian host species in which they generally in-habit the gastrointestinal tract (with or withoutcausing gastritis or other chronic inflammatorydisease), the potential host range for some speciesis quite broad. H. pylori, originally isolated fromhumans, has recently been isolated also from thedomestic cat; this raises the possibility that Heli-cobacter pylori may be a zoonotic pathogen thatcan be transmitted from companion animals tohumans (13). Exploring the possibility of zoonotictransmission of H. pylori, H. hepaticus, or anyother Helicobacter species would require isolationof the organism in question by culture methods.Serologic methods have not yet been refined to thelevel of species specificity. Humans infected withH. pylori mount a serum antibody response to thebacteria that is readily detected by enzyme-linkedimmunosorbent assays and is considered evidenceof ongoing disease (1); mice infected with H. hepa-ticus similarly produce serum antibodies to thatspecies that have been demonstrated by Westernblotting (5). Antisera to H. pylori can be used tovisualize H. hepaticus in mouse liver tissue sec-tions stained by the avidin-biotin complex immu-nohistochemical procedure (5). The cross-reactivity between these two species precludes useof available serologic methods to establishwhether H. hepaticus has infected humans.

Regardless of whether H. hepaticus is itselfcapable of infecting humans, it serves to demon-strate that liver tissue can be persistently infectedby at least one member of the genus Helicobacter,and that liver cancer can be a long-term conse-quence of such infection. This discovery raisesquestions about the existence of a comparablerelationship between liver cancer in humans andunrecognized bacterial infections. Reviews are un-der way of tissue blocks from pathology archivesin search of organisms demonstrable by the

Steiner stain in liver sections from human popu-lations at high risk for liver cancer.

Jerry M. RiceLaboratory of Comparative Carcinogenesis, National

Cancer Institute, Frederick, Maryland, USA

References 1. Parsonnet J, Friedman GD, Vandersteen DP, Chang Y,

Vogelman JH, Orentreich N, et al. Helicobacter pyloriinfection and the risk of gastric carcinoma. N Engl JMed 1991;325:1127-31.

2. Wotherspoon AC, Doglioni C, Diss TC, Pan L, MoschiniA, de Boni M, et al. Regression of primary low-gradeB-cell gastric lymphoma of mucosa-associated lym-phoid tissue type after eradication of Helicobacter py-lori. Lancet 1993;342:575-7.

3. Bayerdörffer E, Neubauer A, Rudolph B, Thiede C,Lehn N, Eidt S, et al. Regression of primary gastriclymphoma of mucosa-associated lymphoid tissue typeafter cure of Helicobacter pylori infection. Lancet1995;345:1591-4.

4. Ward JM, Fox JG, Anver MR, Haines DC, George CV,Collins MJ Jr, et al. Chronic active hepatitis and asso-ciated liver tumors in mice caused by a persistentbacterial infection with a novel Helicobacter species. JNatl Cancer Inst 1994;86:1222-7.

5. Ward JM, Anver MR, Haines DC, Benveniste RE.Chronic active hepatitis in mice caused by Helicobacterhepaticus. Am J Pathol 1994;145:959-68.

6. Garvey W, Fathi A, Bigelow F. Modified Steiner for thedemonstration of spirochetes. J Histotechnology1985;8:15-7.

7. Fox JG, Dewhirst FE, Tully JG, Paster BJ, Yan L,Taylor NS, et al. Helicobacter hepaticus sp. nov., amicroaerophilic bacterium isolated from livers and in-testinal mucosal scrapings from mice. J Clin Microbiol1994;32:1238-45.

8. Battles JK, Williamson JC, Pike KM, Gorelick PL,Ward JM, Gonda MA. Diagnostic assay for Helicobac-ter hepaticus based on nucleotide sequence of its 16SrRNA gene. 1995;33:1344-7.

9. Kita E, Oku D, Hamuro A, Nishikawa F, Emoto M,Yagyu Y, et al. Hepatotoxic activity of Campylobacterjejuni. J Med Microbiol 1990;33:171-82.

10. Taylor NS, Fox JG, Yan L. In-vitro hepatotoxic factorin Helicobacter hepaticus, H. pylori and other Helico-bacter species. J Med Microbiol 1995;42:48-52.

11. Ohshima H, Bartsch H. Chronic infections and inflam-matory processes as cancer risk factors: possible roleof nitric oxide in carcinogenesis. Mutat Res1994;305:253-64.

12. Foltz CJ, Fox JG, Yan L, Shames B. Evaluation ofantibiotic therapies for eradication of Helicobacter hepa-ticus. Antimicrob Agents Chemother 1995;39:1292-4.

13. Handt LK, Fox JG, Dewhirst FE, Fraser GJ, PasterBJ, Yan LL, et al. Helicobacter pylori isolated from thedomestic cat: public health implications. Infect Immun1994;62:2367-74.

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Hemolytic Uremic Syndrome Due to Shiga-likeToxin Producing Escherichia coli O48:H21

in South AustraliaEnterohemorrhagic Escherichia coli (EHEC)

other than serotypes O157:H7 are increasinglyrecognized in association with hemolytic uremicsyndrome (HUS) (1) and have been reported inAustralia (2). While detecting strains of O157:H7has become easier over the years, identifying theexpanding number of other serotypes of EHECalso associated with HUS, with other conditions,and with healthy domestic animals is still verydifficult.

Cases of HUS have been reported in Australiaover a number of years. The most common sero-type found was O111:H-, and Australia’s recentlyreported first HUS outbreak (3) was caused byEHEC O111:H-. We wish to report a case of severeHUS due to serotype O48:H21, which, as far as weknow, has not been previously reported as a causeof HUS. This case occurred in 1993, before sur-veillance of HUS had been initiated; after thiscase, between July and December 1994, 10 casesof HUS (from which four isolates were obtained;two were EHEC O111) were reported to the Aus-tralian Paediatric Surveillance Unit (E. Elliott,pers. comm.).

The patient in the 1993 case was an 8-year-oldgirl, living in a rural setting in the outskirts ofAdelaide, South Australia. Her home was adjacentto a farm on which cows, sheep, and ducks werekept. A kelpie/healer cross puppy was in the housein November 1993. Also kept were a pet galah(Australian cockatoo) and pet fish. She was welluntil 23 December 1993, when she had diarrheadescribed as very smelly and watery “like the juiceof tinned crab.” The diarrhea became bloody on 2January 1994 and was associated with severeabdominal pains which made the patient draw upher legs. She was having bowel movements sixtimes a day, had become very weak, and wasunable to stand. She was admitted to AdelaideChildren’s Hospital on 3 January 1994, and hercondition progressed to anuric renal failure overthe next few days. Serum biochemistry on 7 Janu-ary showed a urea level of 23.3 mmol/L and creat-inine level of 539 µmol/L. Her hemoglobin level fellfrom 157 g/L on 3 January to 86 g/L on 10 January.Her hematocrit fell from 48% to 24%, and her

platelet count fell from 463 x 109/L to 47 x 109/Lon these dates, respectively. The blood film showedmicroangiopathic hemolytic anemia with frag-mented red cells. She required hemodialysis for 3weeks and was discharged from the hospital on 31January 1994.

Apart from the patient’s 5-year-old brother, whohad loose bowel movements for 1 day on 28 Decem-ber 1993, no other family members were affected.An adequate dietary history was not obtained;however, no food had been eaten from commercialfood outlets.

Stool samples were collected on 4 and 5 January1994. The samples were probed for Shiga-liketoxin (SLT)-I and SLT-II genes by polymerasechain reaction (PCR), and the results were posi-tive. Approximately 80% of lactose-fermentingcolonies on MacConkey agar were also SLT posi-tive. No sorbitol-negative colonies were observedon sorbitol-MacConkey agar. In addition to beingcultured for E. coli, the stools were also routinelycultured for Shigella, Salmonella, Yersinia, Vibrio,and Clostridium. In addition, stained concen-trates were examined for Giardia lamblia andEntamoeba histolytica with negative results. Fourtypical E. coli strains were subjected to furthertests. They were typical E. coli, positive in theindole and ONPG tests, negative in the Voges-Proskauer, citrate, TDA, malonate, urease, gela-tine, and H2S tests. The strains fermentedglucose, lactose, mannitol, xylose, rhamnose,arabinose, sorbitol, sucrose, and melibiose. Theydid not ferment inositol, adonitol, salicin, raffi-nose, or amylose. They decarboxylated arginine,lysine, and ornithine. All the strains producedenterohaemolysin (4). The strains were O and Hserotyped (5, 6) and found to be serotype O48:H21.Supernatant preparations were tested on Verocells (7) and found to give typical verocytotoxicreactions in titers of 103 to 104. The supernatantswere also tested by enzyme-linked immunosor-bent assay (ELISA) by using monoclonal antibod-ies 13C4 and 11E10 directed against SLT-I andSLT-II, respectively, and strong reactions withboth antibodies were noted, confirming the pres-ence of both SLTs.

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Stool samples taken from the patient on 8 Feb-ruary 1994 were negative for SLT-I and SLT-IIgenes by PCR and were not cultured further. Stoolsamples from the patient’s brother and local ani-mals were not forthcoming.

That all four E. coli isolates tested were ofserotype O48:H21 and demonstrated identicaltoxigenicity by both PCR and ELISA and the factthat SLT-positive organisms were not found in thestools collected during the patient’s convalescencestrongly suggest that this serotype was the causa-tive organism. The toxicity, virulence, and part ofthe molecular structure of the SLT-II gene derivedfrom the EHEC O48:H21 strain reported here(and whose novel serotype was discovered by theauthors) have recently been described elsewhere(8).

Paul N. Goldwater,* Karl A. Bettelheim†*Microbiology and Infectious Disease Services,

Women’s & Children’s Hospital, Adelaide, South Australia, 5006;

†Biomedical Reference Laboratory,Victorian Infectious Diseases Reference Laboratory,

Fairfield Hospital, Victoria, North Australia,Australia 3078

References1. Bokete TN, O’Callahan CM, Clausen CR, Tang NM,

et al. Shiga-like toxin producing Escherichia coli inSeattle children: a prospective study. Gastroenterology1993; 105: 1724-31.

2. Goldwater PN, Bettelheim KA. The role of entero-haemorrhagic Escherichia coli serotypes other thanO157:H7 as causes of disease. Communicable DiseaseIntelligence 1995;19:2-4.

3. Centers for Disease Control and Prevention. Commu-nity outbreak of hemolytic uremic syndrome attribut-able to Escherichia coli 0111:NM—South Australia,1995. MMWR 1995;44:550-1, 557-8.

4. Beutin L, Montenegro MA, Orskov I, Orskov F, PradaJ, Zimmerman S, et al. Close association of verocyto-toxin (Shiga-like toxin) production with entero-hemolysin production in strains of Escherichia coli. J Clin Microbiol 1989;27:2559-64.

5. Bettelheim KA, Thompson CJ. New method of serotyp-ing Escherichia coli: implementation and verification.J Clin Microbiol 1987;25:781-6.

6. Chandler ME, Bettelheim KA. A rapid method of iden-tifying Escherichia coli “H” antigens. Zentralblatt furBakteriologie, Mikrobiologie und Hygiene 1. AbteilungOriginale. A 1974;129:74-9.

7. Konowalchuk J, Speirs JL, Stavric S. Vero response toa cytotoxin of Escherichia coli. Infect Immun1977;18:775-9.

8. Paton AW, Bourne AJ, Manning PA, Paton JC. Com-parative toxicity and virulence of Escherichia coliclones expressing variant and chimeric Shiga-liketoxin type II operons. Infect Immun 1995;63:2450-8.

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Does Treatment of Bloody Diarrhea due to Shigelladysenteriae Type 1 with Ampicillin Precipitate Hemolytic

Uremic Syndrome?Diarrhea-associated hemolytic uremic syn-

drome (HUS), the most common cause of acuterenal failure in infancy and childhood, is oftenassociated with infection by organisms producingShiga toxin (ST) or Shiga-like toxin (SLT), mainlyverocytotoxin-producing Escherichia coli (VTECO157:H7) and Shigella dysenteriae type 1 (1,2).Although antibiotics are believed to be essentialin treating shigellosis, treatment of S. dysenteriaetype 1 patients with antibiotics to which the or-ganism is resistant has been considered a riskfactor for HUS (3,4).

Until 1993, HUS was rarely reported fromSaudi Arabia. Four cases of diarrhea-associatedHUS due to S. dysenteriae type 1 were identifiedin 1989 (J. Hibbs and A. Mishkas, unpublishedreport), and one case of HUS attributed to plasmatransfusion was documented in 1988 (5).

In May 1993, four dysentery-associated HUScases in two families were reported from north-western Saudi Arabia (Tabuk). S. dysenteriae type1 was isolated from the stool of each HUS patient.The organism was also isolated from 6 of the other10 members of the two families who had dysentery.All isolates were resistant to trimethoprim-sul-famethoxazole, chloramphenicol, tetracycline,and ampicillin but sensitive to nalidixic acid. Thetwo families had just returned from a 1-week visitto relatives in two neighboring villages in Gizan.This densely populated region in southwesternSaudi Arabia has about 1.2 million people livingin more than 4,000 villages; the population isrelatively poor and uneducated, and environ-mental sanitation is generally inadequate.

We defined a case of HUS as any case of bloodydiarrhea (BD) that had all of the following: acuterenal failure (serum urea nitrogen, 18 mg/dL (or6.3 mmol/L); or creatinine, 1.3 mg/dL (or 115mmol/L)); thrombocytopenia (platelet count130,000/mm3); and hemolytic anemia (hemoglo-bin level less than 10 g/dL; or hematocrit less than30%; or appearance of fragmented red cells ondirect microscopy). We standardized the treat-ment of BD in the Gizan region as follows: Noantibiotics were given for treatment of BD at theprimary health care centers (PHCCs) before a

stool specimen was taken for culture and sensitiv-ity testing. After reviewing the preliminary re-sults, we either recommended use of nalidixic acidfor treatment of BD or were guided by the resultsof the stool culture. This protocol was followed formanagement of BD in the entire region.

Parasitologic, bacteriologic, and biochemicaltests and drug treatment regimens were obtainedfor all patients admitted with BD or HUS to theregional referral hospital or five district hospitalsin the outbreak area. BD cases were identifiedthrough hospital admission records, visits toPHCCs in the affected villages, interviews withfamily members of the identified patients, andschool visits. We visited the houses of all HUS andBD patients and interviewed family members toascertain which antibiotic was used to treat theBD patients; mothers were shown bottles andboxes of antibiotics and were asked to identify theantibiotic used for treating the children with BD.

We identified 233 cases of BD occurring fromFebruary through July 1993 among 79 familiesscattered over 19 contiguous villages. Affected vil-lages were predominantly in southern Gizan re-gion near the Yemeni border. One hundred ninetypatients (81.5%) consulted PHCCs; of those, 97(51%) were referred to hospitals, and 81 (43%)were admitted. Thirty-four other BD patientswere admitted directly to hospitals (a total of 115admissions). In nine BD cases patients did notseek medical care including seven (3%) who usedtraditional treatment (the Wicka plant). In 23(10%) patients, 13 male and 10 female, BD devel-oped into HUS. Four isolates of S. dysenteriae type1 that showed the same antibiotic susceptibilitydescribed earlier were obtained from four patientswith BD in different villages in the middle of theoutbreak. We used Cary-Blair transport mediumfor transporting stool specimens collected beforeantibiotic treatment from newly recognized pa-tients with BD. However, community- and hospi-tal-based interviews showed that the sequence ofsymptoms was almost identical in all of the 233BD cases: the condition started with colicky ab-dominal pain and tenesmus (69%), followed bywatery diarrhea (60%), which rapidly became only

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mucus and blood (83%) or blood-streaked (17%).Seven patients (3.0%) had rectal prolapse. S.dysenteriae type 1 was not isolated from any of the23 HUS patients; however, all stool specimenswere taken during antibiotic treatment.

Most BD cases (92.3%) were among Saudis; theremaining 7.7% were among Yemeni patients. NoHUS case occurred among patients over 11 yearsof age. The male/female ratio for both BD and HUSwas 1.3:1. Three boys and three girls with con-firmed HUS died (case-fatality rate = 26.1%); noneof the patients with uncomplicated BD cases died.

Of the 23 HUS patients, 18 (78%) became illwith the disease 2 to 14 days after hospital admis-sion for uncomplicated BD. This compares with ahospital admission rate of 40 (27%) of 147 for

children of the same age with BD from the samevillages (odds ratio = 9.6, 95% confidence interval3.1-35). Five children, aged 8 to 16 months, gotHUS either before or on the day of hospital admis-sion; all had received oral ampicillin at home for 5to 7 days before their illness progressed to HUS.In comparison, two of nine children of the sameage, with BD, who were not hospitalized, receivedampicillin at home (OR = infinite, p value = 0.02,Fisher’s exact test).

Eighteen HUS cases occurred after the patientswere admitted to Samtah and Abu-Arish, two outof five district hospitals. The demographic, clini-cal, and laboratory profiles of BD and HUS casesare shown in Table 1A-C. Six different antibioticswere used in various combinations for treating BD

Places of hospitalization of BD and HUS cases Samtah Abu-Arish KFH Bysh Sabia

No. of BD cases 43 42 13 9 8No. of HUS cases 8 14 - - 1a

Percentage of HUS cases 18.8 33.3 0 0 12.5Median age in years: BD cases 4.0 5.0 7.0 4.0 4.0Median age in years: HUS cases 1.8 2.8 - - 0.8Mean (±SD) of duration (in days) between onset of symptoms and admissionto hospital: BD 3.8 (1.9) 5.5 (1.6) 4.5 (0.4) 3.7 3.9 (2.0) BD complicated with HUS 5.2 (2.6) 4.5 (2.5) - - - HUS diagnosed on admission 13.0 (2.8) 7.5 (0.7) - - 6.0 (0.0)

Laboratory test made on the day ofadmission to the hospitald Non-HUS cases

HUS diagnosed 2-14 daysafter admission to hospital

HUS diagnosed onadmission to hospital

Mean (N)e SD Mean (N) SD Mean (N) SDSerum creatinine 60 (16) 46 63 (3) 79 279 (3) 94Blood urea nitrogin (BUN) 5.4 (23) 5.8 15.3 (3) 12.0 23.0 (3) 6.1Serum sodium 129 (33) 9 137 (3) 4.6 127 (3) 14Serum potassium 3.8 (47) 0.8 3.9 (7) 1.1 4.6 (5) 1.1(Leukocytes [WBC] count) 14.2 (48) 6.0 34.0 (6) 24.7 41.2 (5) 18.8Hemoglobin 11.3 (50) 2.3 12.0 (1) 1.5 6.8 (4) 2.5Hematocrit 36.1 (13) 3.9 NA NA 15 (2) 7.1Thrombocytes (platelets) 322 (5) 250 154 (1) - NA NA(Body temperature on admis-sion)

37.8oC (75) 0.8 37.9oC(18)

0.8 37.9oC (5) 0.9

Ampicillin 36.6 70.0 15.4 11.1 100.0Metronidazole 14.6 55.0 7.7 0 100.0Gentamicin 22.0 22.5 0 55.6 42.9Nalidixic acid 70.7 57.5 61.5 66.7 0 Claforan 2.4 20.0 0 11.1 0 Amikacin 9.8 0 7.7 22.2 28.6

a Community case of HUS. b Percent of cases receiving the corresponding antibiotics. A patient may receive more than one antibiotic. Totals do not add upto 100%. c This table does not include 5 cases diagnosed as HUS on admission and treated as cases of BD. d Creatinine in mg/dL, blood urea nitrogen inmg/dL, sodium in mmol/L, potassium in mmol/L, WBC (white blood cell count) in thousands/µm, hemoglobin level in g/dL, hematocrit, platelets inthousands/mm3. Values shown are for children under 12 years of age only. e N = number of cases of BD diagnosed in the hospital. NA = not available.

Table 1.A. Profiles of children admitted to hospitals with bloody diarrhea (BD) or hemolytic uremic syndrome (HUS)

B. Percentage of 110 BD patients treated with antibioticsb,c

C. Laboratory values of children hospitalized with BD or HUS

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patients in these hospitals Table 1B. Treatmentwith ampicillin prescribed alone or with otherantibiotics except nalidixic acid (Table 2), wasassociated with development of HUS. However,three BD patients who received nalidixic acid de-veloped HUS. Of 12 BD patients (including eightchildren under 12 years of age) who received noantibiotic therapy, none got HUS.

These results support the implication fromBangladesh and from a parallel investigation inSaudi Arabia that inpatient antibiotic treatmentof children with dysentery due to S. dysenteriaetype 1 may precipitate HUS. We have extendedthese observations to show the same associationfor antibiotic treatment at home. Although Abu-Arish and Samtah hospitals received similar num-bers of BD patients, more HUS cases werereported from Abu-Arish hospital, which used am-picillin to treat patients with BD. The variouscombinations of antibiotics used to treat BD pa-tients could be explained by the presence of doc-tors from parts of the world that have different

prescription practices. Three BD patients got HUSdespite the use of nalidixic acid. Resistance tonalidixic acid among S. dysenteriae isolates wasreported from Bangladesh; resistance increasedfrom 2.1% in 1986 to 57.9% in 1990 (6).

We recommend a laboratory-based surveillancesystem to identify and promptly contain emergingoutbreaks. Physicians need to be informed con-tinuously about emerging resistant strains of bac-teria and be cautious when using antibiotics totreat patients with dysentery unless the causativeorganism and the resistance pattern have beenidentified. Parents of children with BD need to beeducated to take their children to the nearesthealth facility as soon as possible.

S. dysenteriae is a delicate bacterium that doesnot withstand adverse conditions (e.g., heat anddryness); prompt plating, preferably at bedside, isrecommended (7). Failure to isolate S. dysenteriaetype 1 from dysenteric stool specimens during thisoutbreak could be attributed to delayed plating ofspecimens, lack of appropriate transport media,

Table 2. Risk of developing hemolytic uremic syndrome (HUS) by antibiotic combination used for treatment of bloody diarrhea(BD), Gizan, Saudi Arabia, 1993

Antibiotic combination group Antibiotic combinations

Dysentery patients

Developing Total (N = 110) HUS (N =18)

BD casesadmitted toSamtah and Abu-Arish Hospitals HUS rate (%) Risk ratio

95% confidence Intervala

Nalidixic acid with or without other antibiotics, but no ampicillanb

N(3/23), N+G (0/7)G+N+C+A (0/1), M+N(0/1), M+N+C (0/2),N+C (0/4)

41 3 28 7.3 1 0.23–4.34

No antibiotic No antibiotic (0/12) 12 0 6 0.0 NCc p value = 0.629d

Antibiotic other than nalidixic acid or ampicillin

A (0/1), C (1/0), G (0/1).M+G (0/1)

4 1 4 25.0 1.58 0.22–11.58e

Ampicillin with or without other antibiotics but no nalidixic acid

28 10 19 35.7 6.90 0.98–48.68

Ampicillin only P (3/3) 6 3 5 50.0 6.11 1.31–28.54 Ampicillin with other antibiotics but no nalidixic acid

P+G (1/2), P+M (2/3), P+M+A (0/2), P+M+C (1/0) P+M+G (3/8)

22 7 14 31.8 10.50 0.54–205.39

Ampicillin and nalidixic acid with or without other antibiotics

P+M+G+N (1/1), P+M+N0/10), P+M+N+C (1/0).P+N (1/8), P+N+A (1/2)

25 4 24 16.0 1.77 0.31–10.21

HUS rate (%) calculated from total number of BD in the five district hospitals using corresponding antibiotic .a Mantel-Haenszel weighted relative risk adjusted tohospital (Epi Info, version 6.02). Analysis restricted for data from Samtah and Abu-Arish hospitals. HUS was not reported from the other three district hospitals.b Reference group. A = amikacin, C = claforan, g = gentamicin, N = nalidixic acid, M = metronidazole, P = ampicillin. Numbers between parentheses in the secondcolumn (antibiotic combination) indicate the (number of patients with HUS who took the corresponding antibiotic combination number or patients with BD who tookthe same antibiotic combination but did not develop HUS in the five district hospitals). c NC = not calculated. d One-tailed Fisher’s exact test. e Adjusted Mantel-Haenszelrelative risk could not be calculated.

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and treatment with antibiotics before stool speci-mens were obtained. Even with direct inoculationof stool specimens in pediatric wards, HUS re-sulted in a low yield of S. dysenteriae type 1 (8,9).

Treatment of BD due to S. dysenteriae type 1with ampicillin may precipitate HUS. It would bevaluable to retrospectively examine this associa-tion in other countries where both dysentery dueto S. dysenteriae type 1 and HUS are reported.

Abdulaziz A. A. Bin Saeed, Hassan E. El Bushra,Nasser A. Al-Hamdan

Field Epidemiology Training Program, Department ofPreventive Medicine, Ministry of Health, Riyadh,

Kingdom of Saudi Arabia

References1. Neild GH. Haemolytic uraemic syndrome in practice.

Lancet 1994;343:398-401.2. Robson WLM, Leung AKC, Kaplan BS. Hemolytic ure-

mic syndrome. Curr Prob Pediatr 1993;23:16-33.3. Butler T, Islam MR, Azad MAK, Jones PK. Risk factors

for development of hemolytic uremic syndrome duringshigellosis. J Pediatr 1987;110:894-7.

4. Al-Qarawi S, Fontaine RE, Al-Qahtani MS. An out-break of hemolytic uremic syndrome associated withantibiotic treatment of hospital inpatients for dysen-tery. Emerging Infectious Diseases 1995;1:138-40.

5. Kher K, Hussein M. Severe haemolytic syndrome: re-port of a child treated with fresh frozen plasma infu-sions and dialysis. Saudi Med J 1988;9:205-7.

6. Bennish ML, Salam MA, Hussein MA, Myaux J, KhanEH, Chakraborty J, et al. Antimicrobial resistance ofShigella isolates in Bangladesh, 1983-1990: increasingfrequency of strains multiply resistant to ampicillin,trimethoprim sulfamethoxazole, and nalidixic acid.Clin Infect Dis 1992;14:1055-60.

7. Keusch GT, Formal SB, Bennish M. Shigellosis. In:Warren KS, Mahmoud AAF, eds. Tropical and geo-graphical medicine 2nd ed. New York: McGraw-Hill,1990:760.

8. Khin-Maung-U, Myo-Khin, Tin-Aye, Myo-Min-Aung,Soe-Soe-Aye, Thane-Oke-Kyaw-Myint, et al. Clinicalfeatures, including hemolytic uremic syndrome, inShigella dysenteriae type 1 infection in children ofRangoon. J Diarrhoeal Dis Res 1987;3:175-7.

9. Srivastava RN, Moudgil A, Bagga A, Vasudev AS.Hemolytic uremic syndrome in children in northernIndia. Pediatr Nephrol 1991;5:284-8.

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An Outbreak of Hemolytic Uremic Syndrome Associatedwith Antibiotic Treatment of Hospital Inpatients for

Dysentery Shiga toxin (ST) from Shigella dysenteriae type

1 is accepted as a cause of hemolytic uremic syn-drome (HUS); however, the reasons why HUSdevelops in only some infected patients are notclear (1). The possibility that antibiotic therapy isassociated with the development of HUS has beenexplored for S. dysenteriae type 1 and for Es-cherichia coli O157:H7 (2–4). In May 1993, duringan outbreak of S. dysenteriae type 1 in Gizan,Saudi Arabia, an association between antibiotictreatment and HUS was also observed (5). Thestrain of S. dysenteriae type 1 was resistant toampicillin, tetracycline, chloramphenicol, andtrimethoprim-sulfamethoxazole (TMP-SMX) andsensitive to nalidixic acid. We report here some ofour preliminary observations for a concurrent out-break.

In response to the Gizan outbreak, a circularwas sent to all regions of Saudi Arabia requestingimmediate reports of S. dysenteriae type 1. Oneregion reported three cases of S. dysenteriae type1 with the same antibiotic resistance pattern. Thepatients were visitors from the Najran region, onthe Yemen border. The affected family reportedthat many other persons in their community ofBarshash, home of about 6,000 Yemeni immi-grants, had recently had dysentery. The regionalhospital in Najran confirmed that several localchildren had been treated for HUS, and an inves-tigation was initiated.

Beginning in February 1993, the numbers ofdysentery patients at the Barshash PrimaryHealth Care Center began to increase from 6patients per week to 110 in mid May. After controlmeasures were initiated, weekly incidence de-creased to zero by late June. According to policy,the Primary Health Care Center treated dysen-tery patients with oral rehydration, whereas thoseadmitted to the regional hospital received antibi-otics. At the regional hospital, S. dysenteriae type1 was isolated from four Barshash residents andone resident of another community.

Between March and May, the illness of 10 (of42) children admitted to the regional hospital fordysentery progressed to HUS from 2 to 10 days(median 5) after admission. For all 10 children,

physicians noted HUS onset as a sudden changein the clinical condition characterized by pallor,puffy face, peripheral edema, or oliguria. Within 2days of clinical onset, blood urea nitrogen (BUN)levels of all 10 children were 10 mmol/L. In ninechildren, the hematocrit fell to below 75% of itsvalue on admission. One child had microcytic hy-pochromic anemia on admission and was trans-fused with one unit of packed red cells; hishematocrit fell from 29.8% after the transfusion to24.6% the day after HUS onset; his BUN level rosefrom 3.1 to 23.5 mmol/L; and his thrombocytecount fell from 529,000/mm3 to 75,000/mm3. Redcell fragments were reported for seven patients.Thrombocytopenia, developed in seven patients;in two, thrombocyte counts decreased from admis-sion values. A leukemoid reaction (≥ 30,000 leuko-cytes/mm3) developed in seven patients.

HUS cases included six children from Bar-shash, one from a contiguous district, one withrelatives in Barshash, and two visiting fromsouthern Gizan region where the concurrent out-break was occurring (5). No child was admittedfrom the community with HUS. Reasons given foradmission were either dysentery or bloody diar-rhea with mild or moderate dehydration. Twodysentery patients who developed HUS were ad-mitted because no one was available to care forthem at home. Characteristics on hospital admis-sion of dysentery patients who did or did notdevelop HUS were similar with the exception ofserum sodium level and BUN (Table 1). Elevationsin creatinine (63 to 133 mmol/L) and urea (6.1 to7.9 mmol/L) levels on admission were mild, andafter intravenous rehydration returned to normal.No enteric pathogens were isolated in stool speci-mens from 35 patients.

All 42 dysentery patients received a variety ofantibiotic combinations composed of ampicillin,TMP-SMX, nalidixic acid, gentamicin, erythromy-cin, and metronidazole. Higher rates of HUS wereobserved among patients receiving antibiotics towhich the locally circulating S. dysenteriae type 1was resistant (ampicillin or TMP-SMX) orantibiotics that are ineffective against Shigella(metronidazole, erythromycin, gentamicin) than

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among patients treated with nalidixic acid (withor without metronidazole) (Table 2). Stratificationof this analysis by elevated creatinine level (62mmol/L) or BUN (6.0 mmol/L) on admission or byweight for age above and below the fifth percentilehad no effect on the magnitude or statistical sig-nificance of these associations. However, stratifi-cation by serum sodium on admission above andbelow 130 mmol/L yielded increased risk ratios of15 (95% confidence interval, 1.6 to 147) for anyineffective antibiotic and 15 (95% confidenceinterval, 2.3 to 99) for ampicillin without nalidixicacid (Mantel-Haentzel analysis).

These strong associations of HUS with priorantibiotic therapy suggest that the antibioticsmay be influencing the progression of S. dysente-riae type 1 to HUS (2,5). The Najran patients hadmilder disease on admission, and the risk ratioswere higher than in the other two reports. Theassumption that S. dysenteriae type 1 caused thedysentery is supported by the isolation of S.dysenteriae type 1 from community members

during a concomitant dysentery outbreak and bythe absence of other ST producing organisms.However, because culture results are lacking, it ispossible that some hospitalized dysentery pa-tients were infected with other organisms.

This investigation was retrospective, and with-out randomization, the selection of patients fortreatment by severity of illness was managed withstratified analysis. All possible indicators of dehy-dration or severity of dysentery on admission werenot available for stratification. However, thesewere also not available to the physicians forselection of patients. Moreover, nalidixic acid wasconsidered effective therapy, and physicians didnot indicate in the medical records that they wereselecting nalidixic acid for less severely ill pa-tients. Because of the variety of antibiotics pre-scribed, the effect of antibiotics given to mostpatients (metronidazole) in combination withother antibiotics could not be evaluated. Theeffectiveness of those given to a few patients(TMP-SMX) could not be assessed.

Table 1. Characteristics on hospital admission of dysentery patients whose illness did or did not develop into hemolytic uremicsyndrome (HUS) during hospitalization, Najran, Saudi Arabia, March through May 1993

Dysentery patients Characteristic Developed HUS (10) Did not develop HUS (32) p valuea

Age (yr mean) 4.4 4.8 0.71Male sex 7 (70%) 23 (72%) 1.0Percentile weight for ageb (median) 15.4 16.3 0.57 Below fifth percentile 6 (60%) 12 (38%) 0.29Days with dysentery (median) 3 3 0.70 Range 2–8 1–14Stools on first hospital day (median) 12.5 9.0 0.23 Range 2–26 2–43Temperature (mean) 38.2oC 38.0oC 0.64 Range 36.8oC–39.4oC 36.5oC–39.4oCHematocrit (mean) 38.9% 38.8% 0.94 Below 35.5% 4 (40%) 7 (23%) 0.43Thrombocytes/mm3 555,000 501,000 0.62 Below 150,000 0 0Leucocytes/mm3 (mean) 11,440 12,300 0.62 Above 12,000 7 (70%) 22 (69%) 1.0 Above 18,000 1 (10%) 4 (13%) 1.0Serum sodium, mmol/L (mean) 130 134 0.02 Below 130 mmol/L 4 (40%) 7 (22%) 0.41Serum potassium, mmol/L (mean) 3.4 3.4 0.86 Below 3.5 mmol/L 5 (50%) 16 (50%) 1.0Serum creatinine, mmol/L (mean) 72 62 0.62 Above 62 mmol/L 5 (50%) 13 (41%) 1.0BUN, mmol/L (mean) 4.1 3.2 0.06 Above 6.0 mmol/L 2 (20%) 2 (6%) 0.24

aDifferences in means by Student’s t-test, in medians by the Kruskal-Wallis test, and in proportions by Fisher’s exact test (two-tailed). bNational Center for HealthStatistics.

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Antibiotic therapy may be associated with HUSin various ways. The antibiotics given may havebeen ineffective, so the infections were allowed torun their natural course to HUS. However, onewould have expected at least a few cases to havedeveloped at home among the hundreds ofBarshash residents with dysentery. Another pos-sibility is that ineffective antibiotics suppressedcompeting microbial flora, allowing less re-strained proliferation of S. dysenteriae type 1.This does not account for the 12% HUS attack ratein patients treated with nalidixic acid. An in-vitrostudy of enhanced Shiga-like toxin I (SLT-1) pro-duction by E. coli O157:H7 suggests another ex-planation. Subinhibitory concentrations ofantibiotics resulted in up to a 400% increase inSLT-I recovery relative to controls (6). This effectwas maximal at maximum subinhibitoryconcentrations of antibiotics, and a quinoline an-tibiotic, ciprofloxacin, yielded the greatest in-crease of toxin. These findings are most consistentwith the epidemiologic findings in this outbreak,including the occurrence of HUS in patientstreated with nalidixic acid and the absence ofHUS in untreated patients in the community.With these considerations, antibiotic treatment of

dysentery from S. dysenteriae type 1 should beapproached with caution.

Sami Al-Qarawi,* Robert E. Fontaine,† andMohammed-Saeed Al-Qahtani*

*Saudi Arabian Field Epidemiology Training Program,Ministry of Health, Saudi Arabia; †EpidemiologyProgram Office, Centers for Disease Control and

Prevention, Atlanta, Georgia, USA.

References1. Moake JL. Haemolytic uremic syndrome: basic science.

Lancet 1994;343:393-401.2. Butler T, Islam MR, Azad MAK, Jones PK. Risk factors

for development of hemolytic uremic syndrome duringshigellosis. J Pediatr 1987;110:894-7.

3. Ostroff SM, Kobayahi JM, Lewis JH. Infections withEscherichia coli O157:H7 in Washington State: thefirst year of statewide disease surveillance. JAMA1989;262:355-9.

4. Pavia AT, Nichols CR, Green DP, et al. Hemolytic-ure-mic syndrome during an outbreak of Escherichia coliO157:H7 infections in institutions for mentally re-tarded persons: clinical and epidemiologic observa-tions. J Pediatr 1990;116:544-51.

5. Bin Saeed AAA, El Bushra HE, Al-Hamdan NA. Doestreatment of bloody diarrhea due to Shigella dysente-riae type 1 with ampicillin precipitate hemolytic ure-mic syndrome? Emerging Infectious Diseases1995;4:134-8.

6. Walterspiel JN, Ashkenazi S, Morrow AL, Cleary TG.Effect of subinhibitory concentrations of antibiotics onextracellular shiga like toxin I. Infection 1992;20:25-9.

Table 2. Risk of developing hemolytic uremic syndrome (HUS) by antibiotic combinations used for in-hospital treatment ofdysentery during a community outbreak of antibiotic-resistant Shigella dysenteriae type 1, Najran, Saudi Arabia, March throughMay 1993

Dysentery patients 95%Developed Risk confidence

Antibiotic combination HUS (10) Total (42) HUS rate/100 ratioa intervalb

Ineffectivec antibiotics without nalidixic 6 12 50 4.3 1.3–15 acidd–j

Ampicillin combinations without nalidixic 5 7 71 6.2 1.9–20 acidd–f

Ineffective antibiotics without nalidixic acid 1 5 20 1.7 0.22–14 or ampicilling–j

Ampicillin and nalidixic acid with (2) or without 1 3 33 2.9 0.40–20 (3) metronidazoleTrimethoprim-sulfamethoxazole, nalidixic acid and metronidazole 0 1 0 0Nalidixic acid with (24) or without (2) metronidazole (reference) 3 26 12 1.0 Reference

a Relative to the reference antibiotic combination (nalidixic acid with or without metronidazole). b Taylor series approximation standard. c Antibiotics to which theoutbreak strain of S. dysenteriae type 1 was resistant (ampicillin, trimethoprim-sulfamethoxazole) or which are ineffective against shigella (metronidazole, gentamicin,or erythromycin). d Ampicillin and metronidazole (4 patients). e Ampicillin, metronidazole, and gentamicin (2 patients). f Ampicillin only (1 patient). g Trimethoprim-sul-famethoxazole and metronidazole (1 patient). h Trimethoprim-sulfamethoxazole, erythromycin, and metronidazole (1 patient). i Metronidazole only (2 patients).j Erythromycin and metronidazole (1 patient).

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Epidemic Cholera in the New World: Translating FieldEpidemiology into New Prevention Strategies

Cholera, a devastating diarrheal disease, hasswept through the world in recurrent pandemicssince 1817. The seventh and ongoing pandemicbegan in 1961 when the El Tor biotype of Vibriocholerae O1 emerged in Indonesia. This pandemicspread through Asia and Africa and finallyreached Latin America early in 1991 (1). Afterexplosive epidemics in coastal Peru, it spread rap-idly and continues throughout Latin America (Fig-ure 1). Because of underreporting, the more than1,000,000 cholera cases and 10,000 deaths re-ported from Latin America through 1994 (Table 1)(2) represent only a small fraction of the actualnumber of infections. Molecular characterizationof V. cholerae O1 strains from Peru has shown thatthey do not match strains from anywhere else inthe world; therefore, the source of the Peruvianepidemic strains remains unknown (3). Moreover,other strains have since appeared in Latin Amer-ica. At least one of these, a strain resistant tomultiple antimicrobial drugs, was first identifiedin Mexico and elsewhere in the world in mid-1991and has since spread widely throughout CentralAmerica (4). The introduction of strains into newareas illustrates the rapid global transfer of patho-gens. V. cholerae O139 Bengal, which emerged asa new cause of epidemic cholera in Asia in 1992,could also appear in Latin America (5).

Such introductions are not easy to prevent,because they may follow the arrival of travelerswho are not aware of their infection or of shipscarrying contaminated ballast water. The key tocontrolling epidemic cholera lies in limiting itsspread by using measures that prevent sustainedtransmission. One measure might be using aninexpensive and effective vaccine to provide last-ing protection; however, no such vaccine yet exists,although progress in vaccine development is beingmade (6-8). Another measure is interruptingtransmission so that the causative organism neverreaches the human host. This approach to preven-tion successfully controlled many epidemic dis-eases in the industrialized world, includingcholera, typhoid fever, plague, and malaria, beforevaccines or antibiotics were developed. Over thelast century, a large engineering infrastructure,built in industrialized nations, has provided safewater and sewage treatment for nearly all people

in these nations and has made sustained trans-mission of cholera in those countries extremelyunlikely. Despite sporadic cases along the U.S.Gulf Coast and repeated introduction of the epi-demic organisms by travelers, epidemic cholerahas not occurred in the United States since thenineteenth century (9,10).

To prevent cholera by interrupting transmis-sion of the organism to the host, it is important tounderstand precisely how the bacteria are trans-mitted. John Snow demonstrated waterbornetransmission of cholera during a large epidemic inLondon in 1856 (11). He and many others sincehave suspected that other routes of transmissionare also important. Epidemiologic investigationsduring the seventh pandemic have documented avariety of specific food and water pathways bywhich the bacteria reach the host, some of whichwere new and unsuspected (12). The El Tor biotypeof V. cholerae O1, for example, multiplies rapidlyin moist foods of neutral acidity (13). This bacte-rium also persists in the estuarine environment inniches that are poorly understood but may involvethe plankton on which shellfish feed. This means

Figure 1. Geographic extent of the Latin Americancholera epidemic over time. Lines represent theadvancing front of the epidemic at different dates. Asof mid-1995, all Latin American countries exceptUruguay have reported cases; no cases have beenreported from the Caribbean.

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that raw seafood can be contaminated naturallybefore it is harvested. Understanding these path-ways of transmission in detail has been central todevising successful control measures to blockthem. For example, advice to drink only boiled orbottled water would be of little use in outbreakswhere the source was actually contaminated food,such as shellfish or leftover rice. On at least oneoccasion, such advice actually worsened the situ-ation because the bottled water was itself contami-nated (14).

When epidemic cholera appeared in LatinAmerica, after an absence of more than 100 years,we conducted a series of eight rapid field investi-gations in collaboration with national publichealth authorities and the Pan-American HealthOrganization to define the pathways of diseasetransmission and the priorities for prevention.Conducted in various settings between February1991 and August 1993, these investigationsguided the initial emergency prevention effortsand the development of sustained preventionmeasures (Table 2) (15-21).

The same case-control method was used foreach investigation. We first interviewed a fewpatients in great detail about what they had

ingested in the 3 days before they became ill,probing for known or potential vehicles of cholera.We then constructed a standardized interviewquestionnaire that asked about possible expo-sures. Using this questionnaire, we interviewedpatients recovering from cholera as well ashealthy persons of the same age and sex who livedin the same neighborhood. By comparing the fre-quency of positive and negative responses amongthe ill and well persons, we could identify theexposures most strongly associated with disease.For example, if 25 of 35 patients, but only 5 of 35matched controls, reported eating sliced mangofrom street vendors in the 3 days before the illnessbegan, the probability of observing this differencein proportions by chance alone is 0.000045, andthe ratio of the odds of exposure is 15, a measureof the strong association between disease and con-suming sliced mangos. When disease is statisti-cally associated with more than one exposure,multivariate analysis can identify truly inde-pendent risk factors. In the above example, “eat-ing food from a street vendor” would not beindependent from “eating sliced mango” if oneusually got sliced mango from a street vendor. This

Table 1. Cholera cases by country, as reported to the Pan American Health Organization, 1991 through 1994 Number of reported cases Country Date of first report 1991 1992 1993 1994

Argentina Feb. 5, 1992 0 553 2,080 889Belize Jan. 9, 1992 0 159 135 6Bolivia Aug. 26 1991 206 22,260 10,134 2,710Brazil Apr. 8, 1991 2,101 30,054 56,286 49,455Chile Apr. 12, 1991 41 73 32 1Colombia Mar. 10, 1991 11,979 15,129 230 996Costa Rica Jan. 3, 1992 0 12 14 38Ecuador Mar. 1, 1991 46,320 31,870 6,833 1,785El Salvador Aug. 19, 1992 947 8,106 6,573 11,739French Guiana Dec. 14, 1992 1 16 2 NRa

Guatemala July 24, 1991 3,652 15,686 30,605 4,227Guyana Nov. 5, 1992 0 5 66 0Honduras Oct. 13, 1991 17 388 2,290 4,965Mexico June 13,1991 2,690 8,162 10,712 4,059Nicaragua Nov. 12, 1991 1 3,067 6,631 7,821Panama Sept.10, 1991 1,178 2,416 42 0Paraguay Jan. 25, 1993 0 0 3 0Peru Jan. 23, 1991 322,562 210,836 71,448 23,887Suriname Mar. 6, 1992 0 2 0 0United States Apr. 9, 1991 26 103 22 34Venezuela Nov. 29, 1991 13 2,842 409 0

Total 391,734 352,300 204,547 112,612a NR = no reports received. Source: ref. 2.

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case-control method can be rapidly carried out inthe field at low cost.

Investigations showed that cholera was beingtransmitted by several distinct mechanisms. Thepredominant route of transmission in a given set-ting depends largely on the degree of sanitationalready achieved. Therefore, a multifaceted ap-proach to prevention is needed. Emergency meas-ures, such as advice to boil drinking water or toheat all foods from street vendors, are difficult tosustain because of their inconvenience and highcost. Moreover, the cost of building large-scalewater treatment and sanitation systems is ex-traordinary, estimated at $200 billion for all ofLatin America (22). The challenge of cholera pre-vention lies in devising low-cost alternatives thatare both effective and sustainable.

Waterborne transmission was identified inseven of the eight investigations. In three of these,the implicated water came from municipal sys-tems or from tanker trucks that reportedly ob-tained water from municipal systems. Waterdelivered through poorly maintained municipalwater systems can be contaminated by sewagebecause of leaky pipes, frequent pressure drops,and the lack of residual chlorine disinfectant in thewater. In developing countries, water is rarelyavailable 24 hours a day so it is usually stored inthe home, where further contamination can easilyoccur. For example, when we measured the in-crease in contamination of the water as it was

distributed and stored in Trujillo, Peru, fecal coli-form counts, an index of sewage contamination,were 1/100 ml in water collected at the source well,2/100 ml at public taps, and 20/100 ml in waterstored in the home (13) In four investigations, theimplicated water was collected from rivers orponds, where direct sewage contamination waslikely. Specific protective practices were also notedin these investigations, including treating waterin the home by boiling it or by adding chlorinebleach, using a small-mouthed vessel to storewater, pouring water out of the storage vesselrather than scooping it out with a cup, and havinghand soap in the home. In one investigation on theAmazon, we found that the local common practiceof adding citrus juice to water to improve its tastewas protective because the acid in the fruit killedVibrio bacteria (14). This observation gave localauthorities a new, inexpensive, and immediatelyavailable emergency control measure.

The first stage of prevention, then, is providingsafe drinking water. As a result of the above find-ings, we have developed and are testing simpleand inexpensive methods of domestic water disin-fection and storage that would also prevent otherdiseases transmitted by the same route. A pilottrial in a periurban area of Bolivia showed thatdisinfecting household water with a calcium hypo-chlorite solution and storing it safely in a specialnarrow-mouthed container was acceptable to acommunity of Aymara Indians (20). Compliance,

Table 2. Mechanisms of transmission of epidemic cholera in Latin America, as determined in eight epidemiologic investigations,1991-1993a

Peru Ecuador El Bolivia Brazil GuatemalaTrujillo Piura Iquitos Guayaquil Salvador Saipina Fortaleza Guatemala CityUrban Urban Urban Urban Rural Rural Rural Urban

Transmission mechanism 3/91 (15) 3/91 (16) 7/91 (17) 7/91 (18) 3/91 (19) 2/92 (20) 6/93 +b 7/93 (21)

Waterborne Municipal water + + + Surface water + + + + Putting hands in + +

water vesselFoodborne Street vendors’ foods + + Street vendors’ beverages + + + Street vendors’ ice/ices + + Leftover rice + + + Fruits/vegetables +Seafood Uncooked seafood + Cooked seafood + +a Reference numbers are in parentheses.b CDC Unpublished data.

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as measured by chlorine residuals in stored water,was high among families using the intervention.The concentration of Escherichia coli bacteria inthe stored water, a measure of fecal contamina-tion, was significantly lower in households thatused the intervention than in neighboring house-holds that used traditional water handling meth-ods (23). A field trial in rural Bolivia showed thatvillagers could generate their own disinfectantsolution by using a simple electrolytic apparatus(24); with the disinfectant and the special watercontainer the villagers provided clean water intheir homes. Households using this interventionhad 40% fewer diarrheal episodes than randomlyselected neighboring families who used traditionalwater-handling methods. The combination ofpoint-of-use disinfection and safer water storagecontainers could have broad effects, including lo-cal empowerment for production of potable water,safer infant foods, and new microindustries for theproduction of disinfectant solutions and water ves-sels (25). Cost-benefit analysis indicates that thisstrategy is cost saving if it prevents more than 20%of diarrheal illnesses (26). Inexpensive disinfec-tant generators are now being manufactured forthis purpose in Ecuador. In Colombia, the numberof cholera cases has dropped dramatically sincelate 1992 when chlorine disinfectant tablets weredistributed for treating household water.

The second major route of cholera transmissionis food contaminated in the market or home. Thisincludes food and beverages sold by street ven-dors, leftover rice, and unwashed fruits and vege-tables. This was an important route in four of theeight investigated areas, including GuatemalaCity, where there was no evidence of waterbornetransmission (21). Foods and beverages sold bystreet vendors are a fixture of urban life through-out the developing world; they are often preparedin unhygienic ways and then held at ambienttemperatures for hours, which permits rapid bac-terial multiplication. Other problems associatedwith food and beverages from street vendors in-cluded using unsafe ice to chill beverages andselling homemade frozen drinks. Leftover rice isan excellent growth medium for V. cholerae O1 andeating leftover rice without reheating it was asso-ciated with illness in three investigations. In oneinvestigation, illness was associated with eatingunwashed produce that was probably splashedwith river water while being transported tomarket in small boats.

Thus, the second stage of cholera prevention isto improve food handling, particularly for foodsand beverages sold by street vendors. Many coun-tries in Latin America have begun educatingstreet vendors in fundamental food safety andlinking this education to licensing (27). By itself,however, education may not improve food safety ifclean water to prepare foods and beverages is notavailable and handwashing and dishwashing withsoap and water are not routine. We are field test-ing a combined strategy of point-of-use disinfec-tion, handwashing with soap, and use of a specialwater/beverage container to improve the micro-bial quality of beverages sold by street vendors.Because street vendors are responsive to customerdemand, teaching consumers to look for streetvendors that are visibly practicing better hygienemay reinforce more hygienic conditions. In addi-tion to these efforts to improve food sold on thestreet, health authorities should advise the publicto reheat leftover rice and wash fruits and vegeta-bles before eating. In Santiago, Chile, suspicionthat cholera was caused by vegetables irrigatedwith fresh sewage led to a ban on this practice; theban not only prevented cholera transmission bythis route, but also decreased the incidence oftyphoid fever and hepatitis A dramatically (28).

Transmission through seafood (identified intwo of the eight investigations) is a third majorroute of cholera transmission, distinct from otherfoodborne mechanisms, because it requires differ-ent prevention strategies. One investigation im-plicated both uncooked seafood and cooked crab,and another implicated cooked seafood eatenwithout reheating. Contaminated seafood alsocaused three outbreaks of travel-associated chol-era in the United States. In the most dramatic, atleast 75 persons contracted cholera after taking aflight from Latin America to California (29); ill-ness was associated with eating cold seafood saladthat was loaded onto the plane in Lima, Peru. Twoother outbreaks followed the informal transport ofcooked crabs from Ecuador to the United States intravelers’ suitcases (30,31). Marine creatures mayharbor V. cholerae O1 before they are harvested ormay be contaminated by seawater used in seasideprocessing plants. In areas where raw and under-cooked seafood are popular, seafood-associatedcholera may occur even if the general level ofsanitation and hygiene is high (32). Vibrios sur-vive light cooking and can subsequently grow if

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the seafood is held for many hours before eating(33).

Preventing seafood-associated cholera in thelong term will depend on maintaining sewage-freeharvest beds and improving sanitation in process-ing plants. In coastal areas where the organismpersists in the environment, even in the absenceof sewage contamination, education to discouragethe consumption of raw or undercooked shellfishis also needed. Thorough cooking provides thegreatest security, but it is sometimes resisted bylocal populations for cultural reasons. “Ceviche,”a popular Latin American dish prepared fromseafood that is marinated in citrus juice for vari-able lengths of time, is a case in point. Prolongedmarination in acidic liquid is likely to inactivatevibrios if the acid can penetrate throughout theflesh and deep organs of the fish or shellfish (34).Further evaluation of this approach is needed, butfor the present, encouraging the use of cevicherecipes that provide sufficient marination timemay be a practical intervention.

In Latin America, as in other parts of the world,epidemiologic field investigations of cholera havedefined the local routes of transmission, identifiedunsuspected and correctable control points, andquantified the effects of emergency measures. Theresults of investigations also have generated spe-cific control strategies targeted to blocking thepredominant routes. While this multistage por-trait of transmission is complex, it is being trans-lated into action and change. The longstandingdeficits in basic urban infrastructure and the needfor new efforts to correct them have never beenmore apparent (35,36). Workable preventionstrategies include better domestic water storagecontainers, point-of-use water disinfection, atten-tion to the education and hygiene of street ven-dors, and simple modifications of traditionalrecipes. Many other diseases are transmitted bythese same waterborne and foodborne routes, sothese control measures may prevent other infec-tions in addition to cholera. If it becomes a cata-lyst for long overdue improvements in the safetyof water and food, epidemic cholera can have afar-reaching impact on the public health of LatinAmerica.

Robert V. Tauxe, M.D., M.P.H., Eric D. Mintz, M.D.,M.P.H., Robert E. Quick, M.D., M.P.H.

National Center for Infectious Diseases, Centers forDisease Control and Prevention, Atlanta, Georgia, USA

References 1. Centers for Disease Control. Cholera—Peru, 1991.

MMWR 1991;40:108-9. 2. Pan-American Health Organization. Cholera in the

Americas. Epidemiol Bull 1995;16:11-3. 3. Wachsmuth IK, Evins GM, Fields PI, Olsvik Ø, Popovic

T, Bopp CA, et al. The molecular epidemiology of chol-era in Latin America. J Infect Dis 1993;167:621-6.

4. Evins GM, Cameron DN, Wells JG, Greene KD, Pop-ovic T, Giono-Cerezo S, et al. The emerging diversity ofthe electrophoretic types of Vibrio cholerae in the West-ern Hemisphere. J Infect Dis 1995;172:173-9.

5. Ramamurthy T, Garg S, Sharma R, Bhattacharya SK,Nair GB, Shimada T, et al. Emergence of a novel strainof Vibrio cholerae with epidemic potential in southernand eastern India. Lancet 1993;341:703-4.

6. Mekalanos JJ, Sadoff JC. Cholera vaccines: fighting anancient scourge. Science 1994;265:1387-9.

7. Sanchez JL, Vasquez B, Begue RE, Meza R, CastellaresG, Cabezas C, et al. Protective efficacy of oral whole-cell/recombinant-B-subunit cholera vaccine in Peru-vian military recruits. Lancet 1994;344:1273-6.

8. Levine MM, Tacket CO. Recombinant live oral vac-cines. In: Wachsmuth IK, Blake PA, and Olsvik Ø,editors. Vibrio cholerae and Cholera. Washington, DC:American Society for Microbiology, 1994:395-413.

9. Rosenberg CE. The cholera years: The United Statesin 1832, 1849, and 1866. Chicago: University of Chi-cago Press, 1987.

10. Blake PA. Epidemiology of cholera in the Americas.Gastroenterol Clin North Am 1993;22:639-60.

11. Snow J. On the mode of communication of cholera. TheCommonwealth Fund. London: Oxford UniversityPress, 1936.

12. Mintz ED, Popovic T, Blake PA. Transmission of Vibriocholerae O1. In: Wachsmuth IK, Blake PA, and OlsvikO, editors. Vibrio cholerae and cholera. Washington,DC: American Society for Microbiology, 1994:345-56.

13. Kolvin JL, Roberts D. Studies on the growth of Vibriocholerae biotype El Tor and biotype classical in foods.J Hyg (Cambridge) 1982;89:243-52.

14. Blake PA, Rosenberg ML, Florencia J, Costa JB,Quintino L do P, Gangarosa EJ. Cholera in Portugal,1974. II. Modes of transmission. Am J Epidemiol1977;105:344-8.

15. Swerdlow DL, Mintz ED, Rodriguez M, Tejada E,Ocampo C, Espejo L, et al. Waterborne transmission ofepidemic cholera in Trujillo, Peru: lessons for a conti-nent at risk. Lancet 1992;340:28-32.

16. Ries AA, Vugia DJ, Beingolea L, Palacios AM, VasquezE, Wells JG, et al. Cholera in Piura, Peru: a modernurban epidemic. J Infect Dis 1992;166:1429-33.

17. Mujica OJ, Quick RE, Palacios AM, Beingolea L, Var-gas R, Moreno D, et al. Epidemic cholera in the Ama-zon: The role of produce in disease risk and prevention.J Infect Dis 1994;169;1381-4.

18. Weber JT, Mintz ED, Cañizares R, Semiglia A, GomezI, Sempértegui R, et al. Epidemic cholera in Ecuador:multidrug resistance and transmission by water andseafood. Epidemiol Infect 1994;112:1-11.

19. Quick RE, Thompson BL, Zuniga A, Dominguez G, deBrizuela EL, de Palma O, et al. Epidemic cholera inrural El Salvador: risk factors in a region covered by acholera prevention campaign. Epidemiol Infect1995;114:249-55.

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20. Gonzales O, Aguilar A, Antunez D, Levine W. An out-break of cholera in rural Bolivia: rapid identificationof a major vehicle of transmission. 32nd InterscienceConference on Antimicrobial Agents and Chemother-apy, Anaheim, 1992. Washington, DC: American Soci-ety for Microbiology 1992; Abstract 937.

21. Koo D, Aragon A, Moscoso V, Gudiel M, Bietti L, Car-rillo N, et al. Epidemic cholera in Guatemala, 1993:transmission of a newly introduced epidemic strain bystreet vendors. Epidemiol Infect 1995; (in press).

22. de Macedo CG. Presentation of the PAHO regionalplan. Proceedings of the Conference: Confronting chol-era, the development of a hemispheric response to theepidemic; 1991 Jul 8-9; Miami: University of Miami,1991;39-44.

23. Quick R, Venczel L, Gonzales O, Damiani E, HighsmithA, Espada A, et al. Impact of narrow-necked watervessels and home chlorination on fecal coliform and E.coli counts in drinking water. 33rd Interscience Con-ference on Antimicrobial Agents and Chemotherapy,New Orleans, 1993. Washington, DC: American Soci-ety for Microbiology, 1993.

24. Quick R, Venczel L, Mintz E, Bopp C, Soleto L, BeanN, et al. Diarrhea prevention in Bolivia through safewater storage vessels and locally-produced mixed oxi-dant disinfectant. 35th Interscience Conference on An-timicrobial Agents and Chemotherapy, San Francisco,1995. Washington, DC: American Society for Microbi-ology, 1995; Abstract 1347.

25. Mintz ED, Reiff FM, Tauxe RV. Safe water treatmentand storage in the home: a practical new strategy toprevent waterborne disease. JAMA 1995;273:948-53.

26. Miller M, Quick R, Mintz E, Tauxe R, Teutsch S. Solidstools and solvent citizens: an effective solution forpreventing diarrhea in developing countries. 34th In-terscience Conference on Antimicrobial Agents andChemotherapy, Orlando, 1994. Washington, DC:American Society for Microbiology, 1994. Abstract1244.

27. Arambulo P, Almeida CR, Cuellar J, Bellotto AJ. Streetfood vending in Latin America. Bull PAHO1994;28:244-54.

28. Alcayaga S, Alcagaya J, Gassibe P. Changes in themorbidity profile of certain enteric infections after thecholera epidemic. Rev Chil Infect 1993;1:5-10.

29. Centers for Disease Control and Prevention. Choleraassociated with an international airline flight, 1992.MMWR 1992;41:134-5.

30. Finelli L, Swerdlow D, Mertz K, Ragazzoni H, SpitalnyK. Outbreak of cholera associated with crab broughtfrom an area with epidemic disease. J Infect Dis1992;166:1433-5.

31. Centers for Disease Control. Cholera—New York,1991. MMWR 1991;40:516-8.

32. Lowry PW, Pavia AT, McFarland LM, Peltier BH, Bar-rett TJ, Bradford HB, et al. Cholera in Louisiana:widening spectrum of seafood vehicles. Arch InternMed 1989;149:2079-84.

33. Blake PA, Allegra DT, Snyder JD, Barrett TJ,McFarland L, Caraway CT, et al. Cholera—a possibleendemic focus in the United States. N Engl J Med1980;302:305-9.

34. Mata L. Efecto del jugo y de la pulpa de frutas acidassobre el Vibrio cholerae. In: El Cólera: Historia, preven-ción y control. San José, Editorial Universidad Estatala Distancia - Editorial de la Universidad de Costa Rica,1992, 275.

35. Sepulveda J, Gomez-Dantes H, Bronfman M. Cholerain the Americas: an overview. Infection 1992;20:243-8.

36. Witt VM, Reiff FM. Environmental health conditionsand cholera vulnerability in Latin America and theCaribbean. J Public Health Policy 1991;12:450-63.

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Are North American Bunyamwera Serogroup VirusesEtiologic Agents of Human Congenital Defects of the

Central Nervous System?In 1941 Gregg provided the first evidence that

rubella virus (family Togaviridae, genus Ru-bivirus) causes human congenital defects (1). Al-though rubella virus infection usually causes amild disease comprising fever and rash, rubellaepidemics have been associated with congenitaldefects in children of women who became infectedduring their first trimester of pregnancy (2). Therisk of in utero rubella infection was reduced bythe introduction of safe and effective vaccines forwomen of child-bearing age. Congenital abnor-malities in fetal or neonatal ruminants also arerelated to exposure of pregnant dams to variousviruses, including bovine viral diarrhea virus(family Togaviridae, genus Pestivirus), the arthro-pod-borne bluetongue viruses (family Reoviridae,genus Orbivirus), Wesselsbron virus (familyFlaviviridae, genus Flavivirus), Rift Valley fevervirus (family Bunyaviridae, genus Phlebovirus),Nairobi sheep disease virus (family Bunyaviridae,genus Nairovirus), and Akabane and Aino (familyBunyaviridae, genus Bunyavirus, Simbu sero-group) viruses (3-10). Infections of livestock withthese viruses may produce low-titer viremia withno apparent clinical disease, or high-titer viremiaand severe clinical illness in the dam. In uteroinfections may result in malformations of the de-veloping fetus, fetal death with resorption, mum-mification, or miscarriage. Stillborn ruminantsmay show various musculoskeletal and centralnervous system defects, including a syndrome ofarthrogryposis with hydranencephaly (AGH).

Bunyamwera serogroup viruses (family Bun-yaviridae, genus Bunyavirus) have been isolatedfrom humans, and some, including Cache Valley(CV) and Tensaw (TEN) viruses, have been iso-lated from symptomatic and asymptomatic largemammals (11). Antibodies to CV virus and otherviruses of the Bunyamwera serogroup are preva-lent in livestock and large wild mammals and inhumans in the Western Hemisphere from Alaskato Argentina (11). Viruses of this serogroup areisolated primarily from mosquitoes of the generaAedes and Anopheles. These viruses have focalgeographic distributions, although some are foundover great expanses. CV virus, a common North

American bunyavirus, has been isolatedprincipally from mosquitoes of the genera Cu-liseta, Aedes, and Anopheles. The geographic dis-tribution of this virus includes all North America,except the extreme southeastern states and south-ern Mexico (11). In the southeastern UnitedStates, TEN virus, also isolated from mosquitoesof the genera Anopheles and Aedes, is the onlyknown representative of the Bunyamwera sero-group, probably because of the range of the prin-cipal vectors and vertebrate hosts; mutualexclusion of these two viruses likely occurs be-cause of cross-protectivity between them (12).

Serologic and temporal associations of infectionwith CV virus and congenital malformations, in-cluding primarily AGH, were observed in sheepnear San Angelo, Texas, between December 1986and February 1987, suggesting that this viruscauses AGH (13). Subsequent outbreaks of similarcongenital defects occurred in sheep in Illinois in1988 (J. Pearson, pers. comm.) and in North Da-kota, Pennsylvania, Maryland, Michigan, and Ne-braska in 1986 and 1987 (14). Antibody to CV virus(but not to other viruses) was found to correlatesignificantly with the occurrence of AGH and othercongenital anomalies during the Texas outbreak(15, 16), and IgM antibody to CV virus was de-tected in colostrum-free neonates with AGH (C.H.Calisher, unpublished data). (Neither maternalIgM nor maternal IgG crosses the placenta insheep; therefore, antibody in fetuses or in neo-nates before they received colostrum indicates fe-tal exposure to an infectious agent [17].)

In 1976, antibody to CV virus was detected inserum from cattle that had delivered calves withAGH in Saskatchewan, Canada, in 1975; however,the prevalence of antibodies to CV virus in thebovine population of that area was not investi-gated (R.E. Shope, pers. comm.). In Texas, in 1981,CV virus was isolated from a sick sheep and froma healthy cow in a herd with reproductive prob-lems (18). This virus also was isolated in Texas in1988 from a sentinel sheep in pasture where anoutbreak of congenital defects had occurred in1986 to 1987. These historical data suggest that

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CV-virus-related congenital malformations maybe more widespread than has been recognized.

Experimental infections have provided furtherevidence that CV virus causes embryonic deathand multiple congenital malformations of sheep(19) and cattle (J. Edwards, pers. comm.). Noassociation of TEN virus and disease in livestock,wild animals, or humans has been reported. Todetermine whether infection with selected Bun-yamwera serogroup viruses, CV and TEN, is asso-ciated with certain human congenital defects, aserosurvey was done with serum samples frommothers of children with microcephaly or macro-cephaly, and the results were compared with thosefrom age- and location-matched controls. The re-sults, reported here, provide the first evidencethat these Bunyamwera serogroup viruses may beetiologic agents of certain congenital defects of thehuman central nervous system.

Two groups of 500 each human serum sampleswere selected at random from an archival collec-tion stored at the National Institutes of Health(NIH), Bethesda, Maryland, and tested for neu-tralizing antibody. These samples were part of acollection of serum specimens obtained between1959 and 1964, at delivery or post partum, (fromabout 50,000 women enrolled under defined pro-tocols in a prospective study of congenital rubellasyndrome. Specimens had been collected from allpregnant women cared for at the particular insti-tution or from women randomly selected by usingthe last digit of their hospital registration number.

For a first series of tests, samples were selectedfrom 200 mothers of children with macrocephaly(head size at least two standard deviations abovethe mean) and from 50 mothers of children withmicrocephaly (head size at least two standarddeviations below the mean). The initial specimenfrom mothers with the respective defects was se-lected for testing. An equal number of mothers ofbabies without obvious central nervous systemdefects were selected as controls, which were age-(±2 years) and site-matched, were registered forthe study in the same month, and were of the samerace as mothers of children with either macro-cephaly or microcephaly. Serum samples comprisingthis first group had been collected from pregnantwomen in Boston, Massachusetts (104), Provi-dence, Rhode Island (20), New York, New York(72), Philadelphia, Pennsylvania (36), Baltimore,Maryland (38), Buffalo, New York (50), Minneapolis,Minnesota (42), Charlottesville, Virginia (38),

Memphis, Tennessee (52), New Orleans, Louisi-ana (36), and Portland, Oregon (12); these weretested for neutralizing antibody to eight bun-yaviruses (Table 1).

An additional 500 samples were tested; 250paired samples, selected as above, from the samearchival collection, two each from women in Bos-ton (120), Buffalo (40), New Orleans (8), New YorkCity (46), Baltimore (8), Charlottesville (12), andMinneapolis (16), including controls (selected asabove). These were tested for neutralizing anti-body to CV virus only, to follow up on results oftests with the first set of samples. One samplefrom each of these women had been collected in thefirst trimester of pregnancy, and the second hadbeen collected at least 3 months later. Serum speci-mens were stored frozen at -20oC until they wereshipped on dry ice (-70oC) to the Centers for Dis-ease Control laboratory at Fort Collins, Colorado.

Twenty-nine of the first 500 serum specimenstested contained neutralizing antibody to CV, 29had antibody to TEN, 29 to Jamestown Canyon,26 to La Crosse, nine to Lokern, and six to Button-willow viruses. None had antibody to Main Drainor Mermet virus. No significant differences wereobserved in antibody prevalences to La Crosse,Jamestown Canyon, Lokern, and Buttonwillowviruses between mothers of microcephalic andmacrocephalic infants and age- and location-matched controls (Table 1). Cases were not re-viewed for other defects.

The prevalence of antibody to CV virus in moth-ers of microcephalic infants was not significantlydifferent from the prevalence of such antibody intheir matched control, but the presence of anti-body to CV virus in mothers was significantlycorrelated with macrocephaly in their infants (χ2,d.f. = 1, n = 400, 4.797 p <0.05) (Table 1).

None of the samples with neutralizing antibodyto CV or TEN virus (titers ranged from 10 to 80)had IgM antibody. To determine whether therewere statistically significant differences betweenprevalences of antibody to CV or TEN virus inmothers of macrocephalic infants and in their age-and site-matched controls, McNemar’s chi-squarewas used. No significant difference was found forthe presence of antibody to CV virus (p >0.05), butthe presence of antibody to TEN virus (p < 0.05 orantibody to either CV or TEN virus (p <0.02) wasrelated to the occurrence of macrocephaly in theinfants of these mothers (Table 2).

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Table 3 summarizes the presence of antibody toCV and to TEN virus in women by hospital loca-tion and birth outcome. When prevalence of anti-body to CV or TEN virus in these women wasanalyzed by location and birth outcome, no statis-tically significant differences were determined(comparative data not shown).

When the second set of 500 specimens (250paired early- and late-pregnancy samples) wastested, specimens from eight women had neutral-izing antibody to CV virus. No diagnostically mean-ingful change in titer was detected between sixsample pairs, but fourfold rises in titer were detectedin two others, (10 to 80, <10 to 40), indicating recentinfections with CV virus or with a closely relatedBunyamwera virus group. Six of the eight women inthis group with antibody to CV virus deliveredmacrocephalic infants, including the two (one inNew Orleans and one in New York City) whosespecimens showed rises in titer to CV virus.

These analyses provide the first evidence thatBunyamwera serogroup viruses in North Americaare associated with congenital defects in humans:the occurrence of macrocephaly in infants waspositively correlated with antibody to CV virus.Antibody to TEN virus and to either CV or TENvirus correlated with microcephaly and withmacrocephaly. The presence of antibody to CV andto TEN viruses corresponded with the known geo-graphic distributions of these viruses within theUnited States. Antibody to either of these virusesin a woman living in an area where that virus isnot known to occur may reflect the close antigenicrelationships and considerable cross-reactivity ofthese Bunyamwera serogroup viruses (22), differ-ences between local virus strains and prototypeviruses, or travel to an area in which the virus doesoccur (23). The two women with diagnosticallysignificant rises in antibody titer to CV virus (onefrom New Orleans, where TEN virus has beenisolated, and one from New York, where CV virushas been isolated) are, as far as we know, the firsttwo persons with documented rises in antibody toa Bunyamwera serogroup virus in North America.Whether either of them had an associated illnesscould not be determined from the records. Thatamong all the women tested they were the onlyones with rises in antibody titer and that both gavebirth to macrocephalic infants is, at the least, afascinating coincidence. IgM antibody in humaninfections caused by other bunyaviruses may notpersist for much more than a few months after

Table 1. Antibody to Cache Valley, Tensaw, La Crosse,Jamestown Canyon, Lokern, or Buttonwillow viruses in moth-ers of microcephalic or macrocephalic infants and matchedcontrolsAntibody to virus Infant’s condition χ 2(p)

Cache Valley Microcephaly 3.840 (0.05)Macrocephaly 4.797 (<0.05)Either 0.915 (>0.20)

Tensaw Microcephaly 4.891 (<0.05)Macrocephaly 4.071 (<0.05)Either 0.329 (>0.20)

Cache Valley or Tensaw Microcephaly 5.983 (<0.02)Macrocephaly 4.806 (<0.05)

La Crosse Microcephaly 0.211 (>0.20)Macrocephaly 1.481 (>0.20)

Jamestown Canyon Microcephaly 0.709 (>0.20)Macrocephaly 0.037 (>0.20)

Lokern Microcephaly 1.010 (>0.20)Macrocephaly 2.041 (>0.10)

Buttonwillow Microcephaly 2.041 (>0.10) Macrocephaly <0.001 (>0.20)

Bunyaviruses used for all tests were prototypes: (Bunyamweraserogroup) CV (strain 6V-633), TEN (A9-171b), Lokern(FMS-4332), Main Drain (BFS-5015), (California serogroup) LaCrosse (Original), Jamestown Canyon (61V-2235), (Simbuserogroup) Buttonwillow (A-7956), and Mermet (AV-782).Samples were tested for antibody by serum dilution-plaquereduction neutralization (20). Briefly, diluted and heat-inactivated (56oC/30 min) serum was added to an equalvolume of virus containing approximately 200 plaque-formingunits (PFU), such that the final virus dilution was 100 PFU.Fresh human serum at a final concentration of 8% was addedto all virus suspensions. Serum-virus mixtures were incubatedat 4oC for 18 h, and 0.1-ml aliquots were dropped in the centerof Vero cultures grown in 6-well plastic plates. After a 45-minperiod of adsorption, cells were overlaid with mediumcontaining 2% agar and further incubated for 70 to 75 h at37oC in 5% CO2-95% air. A second overlay, containingmedium, 2% agar, and 1:25,000 neutral red was then added,and the plates again were incubated until plaques werereadable, usually 12 to 36 h later. A serum specimen wasconsidered positive when it reduced the number of plaques90% relative to control titrations, which ranged from 80 to 150plaques. Samples that were positive in a screening (1:10) testwere titrated for end-point, and the serum titer was taken asthe highest twofold dilution of serum that reduced the numberof plaques 90%.

Although a human positive control for detecting IgM antibodyby capture enzyme-linked immunosorbent assays was notavailable, serum specimens were tested by a modification of apublished technique for detecting IgM antibody to Californiaserogroup viruses (21). Mouse or sheep serum samplescontaining IgM antibody to CV virus or mouse serum with IgMantibody to TEN virus served as positive and negative IgMantibody controls. Statistical analyses were done by chi-squareor McNemar’s chi-square.

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infection (21); IgM antibody has not been detectedin humans with antibody to Bunyamwera sero-group viruses in North America. Therefore, theabsence of IgM antibody in specimens with neu-tralizing antibody likely indicates that these infec-tions were not acute, i.e., they occurred monthsbefore the specimens were collected.

A fundamental problem in establishing a rela-tionship between infection of mammals with CVor TEN virus and attendant congenital anomaliesis the inherent inadequacy of controls. The pres-ence of antibody in humans or other animals withnormal offspring does not necessarily argueagainst the hypothesis that CV virus causes con-genital defects in humans because infection couldhave occurred before pregnancy. Additionally, evenif this virus can be an etiologic agent of congenitalanomalies, preexisting antibody to this virus couldprovide immunity for the mother and protect thefetus from viral infection. Thus, it cannot be deter-mined with certainty whether the presence ofantibody to a virus is coincidental to, or a cause of,the observed congenital anomalies.

Review of NIH records for this relatively smallset of samples suggested that macrocephaly oc-curred somewhat more often when the firsttrimester of pregnancy included the months Apriland May for women living in New Orleans (4/16),Memphis (5/16), and Charlottesville (3/12) and inlate summer-early autumn for women living inBoston (6/49), Minneapolis (3/11), Portland (2/6),and New York City (9/33). In each instance, theseperiods coincide roughly with the appearance ofpopulations of Culiseta, Aedes, or Anopheles mos-quitoes, the vectors of CV and TEN viruses. How-ever, CV virus cannot be implicated in infections

in New Orleans because this virus is not known tooccur there, although TEN virus does.

The relatively small sample sizes in this studyallow statistical interpretation but do not providesufficient support to warrant statements as to thebiological significance of the findings; therefore,we consider these data merely preliminary. Deter-mining whether these data have merit awaits theresults of additional studies of mothers of childrenwith congenital defects and their offspring. Moreextensive studies are also needed to investigatethe influence of gestational phase and fetal devel-opment on congenital defects; establish relation-ships between peak abundance of arthropodvectors and first trimesters of pregnancies; se-quence the genomes of CV and TEN virus strainsfrom various geographic areas and establish rela-tionships between different gene sequences andvirulence in livestock; and develop diagnosticcapacity by using monoclonal antibodies, hybridi-zation assays, polymerase chain reaction, andWestern blotting techniques.

Table 2. Presence of antibody to Cache Valley and Tensaw viruses in mothers of macrocephalic infants and in matched controlsMothers of Antibody-positive Antibody-negativemacrocephalic infants No. controls controls

Antibody to CV virus 16 3 13No antibody to CV virus 184 5 179 McNemar’s testa

Antibody to TEN virus 15 1 14No antibody to TEN virus 185 5 180 McNemar’s testb

Antibody to CV or TEN virus (or both) 19 3 16No antibody to CV or TEN virus 181 5 176 McNemar’s testc

a (13-5)2/18 = 3.556 (d.f. = 1), p > 0.05. b (14-5)2/19 = 4.263 (d.f. = 1), p <0.05. c (16-5)2/21= 5.762 (d.f. = 1), p <0.02.

Table 3. Antibody to Cache Valley and Tensaw viruses inwomen, by location and birth outcome

Antibody to CV virus Antibody to TEN virus

In women with In women with macrocephalic In macrocephalic: In

infants:: controls: infants: controls:Location no. (%) no. (%) no. (%) no. (%) Boston 2/49 (4.1) 1/49 (2.0) 1/49 (2.0) 1/49 (2.0)Providence 0/7 1/7 (14.3) 0/7 1/7 (14.3)New York City 2/33 (6.1) 1/33 (3.0) 1/33 (3.0) 1/33 (3.0)Philadelphia 0/15 2/15 (13.3) 1/15 (6.7) 2/15 (13.3)Minneapolis 1/11 (9.1) 0/1 1/11 (9.1) 0/11 Charlottesville 2/12 (16.7) 0/12 2/12 (16.7 0/12 Memphis 6/16 (37.5) 3/16 (18.8) 5/16 (31.3) 1/16 (6.3)New Orleans 1/16 (6.3) 0/1 2/16 (12.5) 0/16 Portland 2/6 (33.3) 0/6 2/6 (33.3) 0/6

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Given that many members of the family Bun-yaviridae cause congenital defects in naturallyand experimentally infected livestock, or may havesuch a potential (24,25), it would be worthwhile tocontinue investigations with domestic animals andto develop laboratory models to assess the terato-genic potential for humans of CV, TEN, and otherviruses of the family Bunyaviridae.

It is also important to determine the roles of CVand TEN viruses in inducing human congenitaldefects and the relationships between prevalenceof antibody to CV and TEN viruses, prevalence ofcongenital defects, and conception dates, all withrespect to local environmental conditions.

Charles H. Calisher, Ph.D.,* and John L. Sever, M.D.†*Colorado State University, Fort Collins, Colorado, USA;†George Washington University Medical Center, Children’s

National Medical Center, Washington, D.C., USA

AcknowledgmentsThe authors thank Dr. Maneth Gravell and Ms. Dorothy

O’Neill, National Institutes of Health, Bethesda, Mary-land, for selecting, sorting, and shipping serum samples;Mr. Raymond E. Bailey, Centers for Disease Control andPrevention, Fort Collins, Colorado, for statistical advice;Dr. Thomas P.C. Monath, Division of Vector-Borne Infec-tious Diseases, CDC, Fort Collins, for his encouragementand support; and Drs. Barry Beaty, Colorado State Univer-sity, Fort Collins, and John Edwards, Texas A&M Univer-sity, College Station, Texas, for their editorial suggestions.

References 1. Gregg N McA. Congenital cataract following German

measles in the mother. Trans Ophthal Soc Austral1941;3:35-46.

2. Best JM, O’Shea S. Rubella virus. In: Schmidt NJ,Emmons RW, editors. Diagnostic procedures for viral,rickettsial and chlamydial infections, 6th ed. Washing-ton, DC: American Public Health Association1989:731-95.

3. Oberst RD. Viruses as teratogens. Vet Clin North Am;Food Anim Prac 1993:9:23-31.

4. Erasmus BJ. The history of bluetongue. In: Barber TL,Jochim MM, editors. Bluetongue and related or-biviruses. New York: AR Liss, 1985:7-12.

5. Calisher CH, Monath TP. Togaviridae and Flaviviri-dae: the alphaviruses and flaviviruses. In: LennetteEH, Halonen P, Murphy FA, editors. Laboratory diag-nosis of infectious diseases, vol. 2. New York: Springer-Verlag, 1988:414-34.

6. Calisher CH, Shope RE. Bunyaviridae: the bun-yaviruses. In: Lennette EH, Halonen P, Murphy FA,editors. Laboratory diagnosis of infectious diseases,vol. 2. New York: Springer-Verlag, 626-46.

7. Kurogi H, Inaba Y, Takahashi E, Sato K, Omori T,Miura Y, et al. Epizootic congenital arthrogryposis-hydranencephaly syndrome in cattle: isolation ofAkabane virus from affected fetuses. Arch Virol1976;51:67-74.

8. Kurogi H, Inaba Y, Takahashi E, Sato K, Satoda K,Goto Y, et al. Congenital abnormalities in newborncalves after inoculation of pregnant cows with Akabanevirus. Infect Immun 1977:17:338-43.

9. Parsonson IM, Della-Porta AJ, Snowdon WA, MurrayMD. Congenital abnormalities in foetal lambs afterinoculation of pregnant ewes with Akabane virus. Aus-tral Vet J 1975:51:585-6.

10. Coverdale OR, Cybinski DH, St. George TD. Congeni-tal abnormalities in calves associated with Akabaneand Aino virus. Austral Vet J 1978:54:151-2.

11. Calisher CH, Francy DB, Smith GC, Muth DJ, LazuickJS, Karabatsos N, et al. Distribution of Bunyamweraserogroup viruses in North America, 1956-1984. Am JTrop Med Hyg 1986;35:429-43.

12. Calisher CH. Evolutionary significance of the taxo-nomic data regarding bunyaviruses of the family Bun-yaviridae. Intervirology 1988;29:268-76.

13. Crandell RA, Livingston CW. Laboratory investigationof a naturally occurring outbreak of arthrogryposis-hy-dranencephaly in Texas sheep. J Vet Diagn Invest1988;1:62-5.

14. Rook JS, Yamini B, Steficek B. AGH syndrome: coop-eration answers questions. National Wool Grower1988(April):24-5.

15. Edwards JF, Livingston CW, Chung SI, Collisson EC.Ovine arthrogryposis and central nervous systemmalformations associated with in utero Cache Valleyvirus infection: spontaneous disease. Vet Pathol1989;26:33-9.

16. Edwards JF. Cache Valley virus. Vet Clin North Am;Food Anim Prac 1994;10:515-24.

17. Campbell SG, Siegel MJ, Knowlton BJ. Sheep immu-noglobulins and transmission to the neonatal lamb.N Z Vet J 1977;25:361-5.

18. McConnell S, Livingston C Jr, Calisher CH, CrandellR. Isolations of Cache Valley virus in Texas, 1981. VetMicrobiol 1987;13:11-8.

19. Chung SI, Livingston CW Jr, Edwards JF, Gauer BB,Collisson EW. Congenital malformations in sheep re-sulting from in utero inoculation of Cache Valley virus.Am J Vet Res 1990;51:1645-8.

20. Lindsey HS, Calisher CH, Mathews JH. Serum dilu-tion neutralization test for California group virus iden-tification and serology. J Clin Microbiol 1976;4:503-10.

21. Calisher CH, Pretzman CI, Muth DJ, Parsons MA,Peterson ED. Serodiagnosis of La Crosse virus infec-tions in humans by detection of immunoglobulin Mclass antibodies. J Clin Microbiol 1986;23:667-71.

22. Calisher CH, Lazuick JS, Lieb S, Monath TP, CastroKG. Human infections with Tensaw virus in southFlorida: evidence that Tensaw virus subtypes stimu-late the production of antibodies reactive with closelyrelated Bunyamwera serogroup viruses. Am J TropMed Hyg 1988;39:117-22.

23. Calisher CH, Sabattini MS, Wolff KL, Monath TP.Cross-neutralization tests of South American isolatesof Cache Valley virus revealing the existence of multi-ple subtypes. J Trop Med Hyg 1988;39:202-5.

24. Parsonson IM, Della-Porta AJ, Snowdon WA. Develop-mental disorders of the fetus in some arthropod-bornevirus infections. Am J Trop Med Hyg 1981;30:660-73.

25. McPhee DA, Parsonson IM, Della-Porta AJ, JarrettRG. Teratogenicity of Australian Simbu serogroup andsome other Bunyaviridae viruses: the embryonatedchicken egg as a model. Infect Immun 1984;43:413-20.

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Lymphocytic Choriomeningitis Virus:An Unrecognized Teratogenic Pathogen

Lymphocytic choriomeningitis virus (LCMV),the first member of the arenavirus family to beisolated, is the causative agent of a zoonosis ac-quired from chronically viremic mice or hamsters(1). The clinical spectrum of acquired humanLCMV infection ranges from inapparent andasymptomatic to, in rare instances, severelysymptomatic, systemic, and fatal central nervoussystem (CNS) disease. Intrauterine LCMV infec-tion has resulted in fetal or neonatal death, as wellas hydrocephalus and chorioretinitis in infants(2-6). We have diagnosed congenital LCMV infec-tion in three infants (7) and have collated pub-lished and unpublished data on three additionalaffected infants (8, G.R. Istre, pers. comm.). Thisreport briefly summarizes the salient features ofthe infection in five of these six American infantsand outlines the similarities between these andfeatures observed earlier in Europe. We suggestthat LCMV is a more frequent cause of CNS dis-ease in newborns than previously recognized.

Congenital LCMV infection was first recog-nized in Great Britain in an infant who died at 12days of age (3). Subsequently, fetal infection withspontaneous abortion (2) and congenital infectionin liveborn infants with hydrocephalus and chori-oretinitis were documented in Germany (4),France (6), and Lithuania (5). We have recentlydocumented congenital LCMV infection in threeinfants from Arizona (7) and have obtained infor-mation regarding three additional neonates fromArizona, Nebraska (8), and Texas (G.R. Istre, pers.comm.). Detailed clinical and laboratory data areavailable for five of the six infants. All displayednonobstructive hydrocephalus with periventricu-lar calcifications, chorioretinitis, and psychomotorretardation. One of the five infants had sensor-ineural deafness. None of the infants had cardiacabnormalities. Two infants have had follow-upophthalmologic and audiologic examinationswhich have shown neither the progression ofchorioretinitis nor the development of new audi-tory deficits. Toxoplasma gondii, cytomegalovirus,Herpes simplex virus, rubella, enterovirus, andTreponema pallidum infections were excluded byculture or serology in all infants. The diagnosis ofcongenital LCMV infection was confirmed in allinfants by immunofluorescence antibody (IFA)

and enzyme-linked immunosorbent assays(ELISAs). In addition, serum, CSF, urine, andthroat wash specimens from two infants wereinjected into Vero cell monolayers. Neither cytopa-thic effect nor LCMV antigens were detected afterincubation. Because virus isolation was only at-tempted after the disease was first diagnosedwhen the children were 10 months of age, failureto isolate LCMV was not unanticipated.

Laboratory diagnosis of LCMV infection is gen-erally made by serologic techniques. IFA is a moresensitive diagnostic method than either comple-ment fixation or neutralizing antibody techniques(9,10). The newer ELISAs are now being used toevaluate congenitally infected infants. Testing thechild’s serum and CSF and a simultaneously ob-tained serum specimen from the mother yields themaximum information if done as soon after birthas possible.

The mothers of four of the five infants in thisreport had a history of febrile illness during preg-nancy, in contrast to a minority of mothers ofaffected infants previously reported. TypicalLCMV infection in adults is a biphasic diseasewith fever, malaise, myalgias, anorexia, nausea,vomiting, pharyngitis, cough, and adenopathy fol-lowed by defervescence and a second phase of CNSdisease. However, CNS symptoms may appearwithout any prodrome or may never develop. Men-ingitis and meningoencephalitis are the most fre-quent neurologic manifestations of disease,although myelitis, Guillain-Barré syndrome, andsensorineural deafness have been reported (11).Between 1941 and 1958, 8% to 11% of viral CNSsyndromes in hospitalized patients in a Washing-ton, D.C., medical center were etiologically associ-ated with LCMV (12). Arthritis, parotitis, orchitis,myocarditis, and rash have also been noted (13).Clinical interest in LCMV, however, has not beenmaintained, and the disease is rarely considereddespite improved serodiagnostic methods.

Although a history of contact with rodents andtheir excreta is of diagnostic utility, it is not uni-versally present. A maternal history of rodentexposure was elicited for three of our five infants.Wild mice (Mus musculus) and hamsters infectedin utero with LCMV during maternal viremiadevelop both persistent viremia and viruria. The

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virus is transmitted to humans by direct animalcontact; by contact with infected rodent saliva,nasal secretions, urine, feces, semen, and milk;and by infectious aerosols (1). Human-to-humantransmission has not been documented. The dis-tribution of LCMV is highly variable within mousepopulations. Seasonal, annual, and cyclical vari-ations in rodent density and infection have beenpostulated but remain inadequately studied (14).LCMV spreads to humans in rural settings orwhen human habitats are substandard. Infectedlaboratory and pet rodents have also been associ-ated with disease in humans (1). Serologic surveysand clinical studies have documented both epi-demic and endemic human infection in Europeand the Americas. In Baltimore, 9.0% of housemice and 4.7% of residents have had measurableLCMV antibody (15,16).

We hypothesize that congenital LCMV infec-tion is generally undiagnosed and may account forunexplained hydrocephalus with microcephaly ormacrocephaly, deafness, blindness, and mental re-tardation (three of the five infants in this reportwere referred for infectious disease consultationby pediatric geneticists, and two were referred bypediatric neurologists). No accurate data areavailable regarding the prevalence and persist-ence of LCMV antibodies in unselected infants,children, and adults in diverse geographic localesor in children with unexplained visual and/orauditory deficits, microcephaly, and retardation.Increased recreational activities in rural environ-ments, rehabilitation of and habitation in olderrodent-infected domiciles, and acquisition of un-screened rodents for pets or laboratory use pose asyet undefined risks for LCMV infection to thefetus, child, and adult. The need for further re-search to define the frequency of LCMV infectionin human and animal populations is clear. LCMVinfection can best be prevented by educating thepublic and medical professionals on the hazards ofcontact with infected rodents.

Leslie L. Barton, M.D.,* C.J. Peters, M.D.,† T.G. Ksiazek, D.V.M., Ph.D.†

*University of Arizona Health Sciences Center,Department of Pediatrics and Steele Memorial

Childrens Research Center, Tucson, Arizona, USA;†National Center for Infectious Diseases, Centers for

Disease Control and Prevention, Atlanta, Georgia, USA

AcknowledgmentsWe thank Drs. Jane Wilson, Gregory Istre, Stephen

Chartrand, and Laurie Seaver for patients’ information;

Dr. Matafija Seinbergas for his enthusiastic support; andMs. Amy Sites for technical support.

References 1. Jahrling PB, Peters CJ. Lymphocytic choriomeningi-

tis: a neglected pathogen of man. Arch Pathol Lab Med1992;116:486-8.

2. Ackermann R, Stammler A, Armbruster B. Isolierungvon Virus der lymphozytaren Choriomeningitis ausAbrasionsmaterial nach Kontakt der Schwangerenmit einem Syrischen Goldhamster (Mesocricetus aura-tus). Infection 1975;3:47-9.

3. Komrower GM, Williams BL, Stones PB. Lymphocyticchoriomeningitis in the newborn: probable transpla-cental infection. Lancet 1955;1:697-8.

4. Ackermann R, Korver G, Turss R, Wonne R, Hochge-sand P. Prenatal infection with the lymphocyticchoriomeningitis virus. Dtsch Med Wochenschr1974;13:629-32.

5. Seinbergas MM. Hydrocephalus due to prenatal infec-tion with the lymphocytic choriomeningitis virus. In-fection 1976;4:185-91.

6. Chastel C, Bosshard S, Le Goff F, Quillien MC, GillyR, Aymard M. Infection transplacentaire par le virusde la choriomeningite lymphocytaire: resultats duneenguete serologique retrospective en France. NouvPress Med 1978;7:1089-92.

7. Barton LL, Budd SC, Morfitt WS, et al. Congenitallymphocytic choriomeningitis virus infection in twins.Pediatr Infect Dis J 1993;12:942-6.

8. Larsen PD, Chartrand SA, Tomashek KY, Hauser LG,Ksiazek TG. Hydrocephalus complicating lymphocyticchoriomeningitis virus infection. Pediatr Infect Dis J1993;12:528-31.

9. Lewis VJ, Walter PD, Thacker WL, Winkler WG. Com-parison of three tests for the serological diagnosis oflymphocytic choriomeningitis virus infection. J ClinMicrobiol 1975;2:193-7.

10. Lehmann-Grube F, Kallay M, Ibscher B, Schwartz R.Serologic diagnosis of human infections with lympho-cytic choriomeningitis virus: comparative evaluationof seven methods. J Med Virol 1979;4:125-36.

11. Lehmann-Grube F. Diseases of the nervous systemcaused by lymphocytic choriomeningitis virus andother arenaviruses. In: Handbook of clinical neurology.New York: Elsevier, 1989;12:355-81.

12. Meyer HM, Johnson RT, Crawford, IP, Dascomb HE,Rogers NG. Central nervous system syndromes of “viral”etiology: a study of 713 cases. Am J Med 1960:334-47.

13. Lewis JM, Utz JP. Orchitis, parotitis and menin-goencephalitis due to lymphocytic-choriomeningitis vi-rus. N Engl J Med 1961;265:776-80.

14. Childs JE, Peters CJ. Ecology and epidemiology ofarenaviruses and their hosts. In: The Arenaviridae.New York: Plenum, 1993:331-84.

15. Childs JE, Glass GE, Korch GW, Ksiazek TG, LeducJW. Lymphocytic choriomeningitis virus infection andhouse mouse (Mus musculus) distribution in urbanBaltimore. Am J Trop Med Hyg 1992;47:27-34.

16. Childs JE, Glass GE, Ksiazek TG, Rossi CA, BarreraOro JG, Leduc JW. Human-rodent contact and infec-tion with lymphocytic choriomeningitis and Seoul vi-ruses in an intercity population. Am J Trop Med Hyg1991;44:117-21.

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Hemolytic Uremic SyndromeAlong with a report of the first outbreak of

hemolytic uremic syndrome (HUS) caused byShiga-like toxin (SLT) producing E. coli in Austra-lia (1), this issue of Emerging Infectious Diseasespresents three papers detailing the investigationsof pediatric HUS cases linked to Shiga toxin (ST)and SLT producing bacteria. Goldwater and Bet-telheim present a case of pediatric HUS associ-ated with SLT producing Escherichia coli (SLTEC)O48:H21 in South Australia; this strain has notpreviously been recognized as an SLTEC. Saeedet al. report on the increasingly common identifi-cation of HUS in Saudi Arabia, its association withmultiple-antibiotic-resistant Shigella dysenteriaetype 1, and the inherent dangers of treating suchpatients with ampicillin and nalidixic acid. Al-Qawari et al. report on the results of active sur-veillance for dysentery and HUS in Saudi Arabiaand discuss a possibly elevated risk for HUS inpatients with bloody diarrhea who are hospital-ized and treated with nalidixic acid during anoutbreak of S. dysenteriae type 1.

The three papers raise a number of importantissues regarding HUS. First, it is clear that a largenumber of SLT producing bacteria have the poten-tial to cause HUS, particularly among children.Current research has focused on E. coli O157:H7,which since the early 1980s has emerged as amajor foodborne cause of bloody diarrhea, hemor-rhagic colitis, and HUS since the early 1980s (5-7).However, the large outbreak of pediatric HUS inSouth Australia in 1995 caused by foodborne E.coli O111:HNM has demonstrated that minorpathogens can emerge as major causes of HUS (1).Goldwater and Bettelheim (5) and other re-searchers have identified a number of E. coli sero-types isolated from patients with HUS (6,7).A-Qawari et al. and Saeed et al. offer a timelyreminder that S. dysenteriae type 1, a pathogenwith a human-only reservoir, is an equally seriouscontender in HUS etiology and pathogenesis whenconditions facilitate the person-to-person trans-mission of pathogens.

The second key issue raised by the latter twopapers concerns treatment of bloody diarrhea.Both discuss the potential for antibiotic (am-picillin and nalidixic acid)-mediated HUS andconclude that this issue should be carefully evalu-ated before antibiotics are used to manage bloodydiarrhea. Saeed et al. note that the wide variety

of antibiotics used to treat bloody diarrhea inSaudi Arabia could be explained by the variousprescription practices of doctors recruited fromdifferent parts of the world. Antibiotic resistanceis a worrying component of the mechanisms ofemerging infectious diseases. Inappropriate anti-biotic use is a key factor in the development ofresistance, and major efforts must be directedtowards educating physicians on effective pre-scribing practices.

Central to all three papers is the need for sur-veillance of organisms that cause bloody diarrhea,hemorrhagic colitis, and HUS, as well as forknowledge of the local epidemiology of SLTECs,their potential sources, and the optimal way toinvestigate and manage outbreaks. Goldwaterand Bettelheim discuss the characteristic disap-pearance of E. coli from patients’ stools after thedevelopment of HUS and, therefore, the impor-tance of early detection in cases of bloody diar-rhea. Laboratory testing of bloody diarrhealspecimens is clearly critical to understanding theepidemiology of toxin-producing organisms thatrelate to the development of HUS (8). However,testing can be difficult, time-consuming andcostly. Not all laboratories routinely test forSLTECs or have the capacity to do so. In Australia,for example, using polymerase chain reaction(PCR) technology to detect SLT genes is expen-sive: a negative test result costs approximately$A15, but if the results are positive, the cost risesto around $A250 when the SLTEC is isolated andtyped.

Human surveillance is essential to the earlydetection of outbreaks and to the critical assess-ment of the impact on public health of new ap-proaches to food safety (2,8). We conservativelyestimate that the South Australian HUS outbreakhas cost around $A20 million in direct and indirectcosts, with major impacts being felt by industry.This must surely be considered when contemplat-ing the costs of surveillance. One approach maybe to use PCR techniques on all samples of bloodydiarrhea in children under the age of 16 becauseif surveillance is to be effective, it must be specific(9). Intermittent surveys, or the use of sentinellaboratories for all cases of diarrhea (8) could beundertaken and mandatory notification of HUSinstituted.

Compulsory notification of Shigella infection isa requirement in Australia, and includingSLTECs on the list of notifiable diseases is being

Commentary


considered. A national surveillance scheme forHUS was established in 1994, although notifica-tion is not mandatory. Without formal notificationrequirements, good reporting of HUS has beenassociated with either clustering of cases or thefact that few hospitals in a region have the capac-ity to manage these cases (10).

Although more attention has been focused onE. coli O157:H7, S. dysenteriae is likely the mostcommon cause of HUS in children worldwide andmore attention needs to be given to this pathogenin terms of surveillance and control. A strong andhealthy public health infrastructure is required toaddress the infectious disease issues raised byHUS (11).

Mary Beers,* Scott Cameron†*National Centre for Epidemiology and PopulationHealth, and South Australian Health Commission;

†Communicable Disease Control Unit, South AustralianHealth Commission, Adelaide, Australia

References:1. Cameron AS, Beers MY, Walker CC, et al. Community

outbreak of hemolytic uremic syndrome attributable toEscherichia coli O111:NM—South Australia, 1995.MMWR 1995;44:550-8.

2. Waters JR, Sharp JC, Dev VJ. Infection caused byEscherichia coli O157:H7 in Alberta, Canada, and inScotland: a five-year review, 1987-1991. Clin Infect Dis1994;19:834-43.

3. Bell BP, Goldoft M, Griffin P, Davis MA, Gordon DC,Tarr P, et al. A multistate outbreak of Escherichia coliO157:H7-associated bloody diarrhea and hemolyticuremic syndrome from hamburgers: the Washingtonexperience. JAMA 1994;272:1349-53.

4. Alexander ER, Boase J, Davis M, et al. Escherichia coliO157:H7 outbreak linked to commercially distributeddry-cured salami—Washington and California, 1994.MMWR 1995;44:157-60.

5. Goldwater PN, Bettelheim KA. The role of enterohaem-orrhagic Escherichia coli serotypes other than O157:H7as causes of disease in Australia. Communicable Dis-eases Intelligence 1995;19:2-4.

6. Caprioli A, Luzzi I, Rosmini F, Resti C, Edefonti A,Perfumo F, et al. Communitywide outbreak ofhemolytic-uremic syndrome associated with non-O157verocytotoxin-producing Escherichia coli. J Infect Dis1994;169:208-11.

7. Griffin PM, Tauxe RV. The epidemiology of infectionscaused by Escherichia coli O157:H7, other enterohaem-orrhagic E. coli, and the associated hemolytic uremicsyndrome. Epidemiol Rev 1991;13:60-98.

8. Alexander ER. Editorial response: surveillance of Es-cherichia coli O157:H7—a necessity for the preventionof an emerging infectious disease. Clin Infect Dis1994;19:844-5.

9. Satcher D. Emerging infections: getting ahead of thecurve. Emerging Infectious Diseases 1995;1:1-6.

10. Siegler RL, Pavia AT, Christofferson RD, Milligan MK.A 20-year population-based study of postdiarrhealhemolytic uremic syndrome in Utah. Pediatrics1994;94:35-40.

11. MacDonald KL, Osterholm MT. The emergence of Es-cherichia coli O157:H7 infection in the United States:the changing epidemiology of foodborne disease. JAMA1993;269:2264-6.

Commentary


Guidelines on the Risk forTransmission of Infectious AgentsDuring Xenotransplants

An increasingly critical shortage of human do-nors has limited the availability and benefit oforgan and tissue transplantation. This chronicshortage, coupled with recent scientific andbiotechnological advances, has been a catalyst fornew therapeutic approaches directed at using ani-mal tissues in humans. The use of xenogeneictissues and organs for transplantation or perfu-sion has raised concerns about the potential ofboth recognized zoonotic pathogens and unknownxenogeneic agents to infect individual human re-cipients and then spread through human popula-tions.

Public health guidelines intended to minimizethe risk for transmission of known pathogensthrough human-to-human transplantation exist.Similar guidelines addressing the issue of infec-tious agents that may be associated withxenotransplantation are being jointly developedby Public Health Service working groups at theCenters for Disease Control and Prevention(CDC), the Food and Drug Administration, andthe National Institutes of Health. A provisionaldraft of these guidelines will be published in theFederal Register in late 1995. Public comment onthe proposed guidelines is invited. Critical reviewby members of the transplant community is par-ticularly sought. Publication of a final version ofthese guidelines in CDC’s Morbidity and MortalityWeekly Report is planned for the spring of 1996.

Louisa E. ChapmanNational Center for Infectious Diseases

Centers for Disease Control and PreventionAtlanta, Georgia, USA

Emerging Infectious DiseasesFeatured at ICAAC/IDSA Meeting

Emerging infectious diseases were highlightedrecently at a joint meeting of the InterscienceConference on Antimicrobial Agents and Chemo-therapy (ICAAC) and the Infectious Diseases So-ciety of America (IDSA) in San Francisco. In hisopening address, IDSA President Vincent Andri-ole stated that the topic of most pressing concern

to both organizations was new and reemergingpathogens. Presentations were made on the fol-lowing subjects: arenavirus hemorrhagic fevers;changing virulence of streptococcal infections;cryptosporidia, cyclospora, and microsporidia;dengue/dengue hemorrhagic fever; emerging fun-gal pathogens; epidemic diphtheria in the newlyindependent states; Escherichia coli O157:H7;Helicobacter pylori; human ehrlichioses; new lym-photropic herpesviruses; and rabies.

Common themes emanated from the presenta-tions. The speakers noted that infectious diseasescontinue to occur throughout the world, both spo-radically and as outbreaks, because of multiplefactors. They observed that the incidence andprevalence of infectious diseases are increasing incertain populations, particularly among immuno-compromised persons. Additionally, new infec-tious diseases and etiologic agents continue to beidentified with remarkable frequency, and micro-organisms are being identified as causes of chronicdiseases, including cancer. Several presenters ex-pressed concern about the migrations of animalreservoirs and arthropod vectors into new popula-tions and geographic areas. The speakers alsocalled for additional support for the public healthinfrastructure and for basic sciences that providethe foundation for infectious disease preventionand treatment.

Building a Geographic InformationSystem (GIS) Public HealthInfrastructure for Research andControl of Tropical Diseases

A course on using Atlas GIS software and asso-ciated peripherals, such as digitizing tablets andglobal positioning systems (GPS), to build a GISpublic health infrastructure in Latin Americancountries was taught August 7 to 18, 1995, at theCenters for Disease Control field station in Gua-temala City, which includes the Medical Entomol-ogy Research Training Unit housed at theUniversidad del Valle de Guatemala. The coursewas funded by the Special Programme on Re-search and Training in Tropical Diseases and pre-sented by the Latin American Tropical DiseaseResearch Training Consortium. Course

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instructors included statisticians and epidemiolo-gists from the Division of Parasitic Diseases, Na-tional Center for Infectious Diseases, Centers forDisease Control and Prevention in Atlanta, Geor-gia, and in Guatemala City, Guatemala, and stafffrom the National Aeronautics and Space Admini-stration, Center for Health Application of Aero-space Related Technologies, Ames ResearchCenter, Sunnyvale, California.

Objectives of the training included the follow-ing: mastery of the principles and general conceptsof all GIS systems; use of Atlas GIS/DOS to asso-ciate map files with databases to produce thematicmaps, manipulate various layers (rivers, high-ways, village locations) of the map files to producecustomized maps, create buffers around geo-graphic features, and use them in simple analyses;designing georeferenced data files that can be readby the GIS; digitizing paper maps to acquire newdata for building a GIS; use of GPS to obtainlatitudes, longitudes, and elevations of villagesand other major landmarks and to use this infor-mation in the GIS; and mastery of importing/ex-porting databases and map files.

The course was designed to enable participantsto set up and use a GIS for research, planning, oroperational purposes. Participating were institu-tions from Mexico (two teams), Colombia (two),Puerto Rico, Costa Rica, Venezuela, Guatemala(two), Ecuador, and Brazil. Each team came to thecourse with ideas, maps, and data pertaining to anexisting project that would be continued at theirhome institution. Student project areas includedonchocerciasis, malaria, water sanitation, leish-maniasis, and public health and natural resourceutilization/preservation. The students weretaught digitizing and were asked to use Guineaworm surveillance data to create their own GIS.

A full day was devoted to geographic analyses.Topics covered included aggregating data from onegeographic layer to another, combining geographicfeatures with common database values, and com-bining selected features to form new map layers.A workshop on remote sensing, GIS, and imageclassification explained that satellite imagery andremotely sensed data are obtained by measuringreflectance on seven spectral frequencies and thatground cover can be partially deduced by theamount of reflectance at each band. Field exer-cises to practice GPS use in the Lake Atitlan areafollowed. Another workshop covered advanceddigitizing and gave each team a good start on the

digitizing part of their projects. Individual instruc-tions were given on how to import map files fromother GIS programs into Atlas GIS. Lastly, theGuatemalan onchocerciasis GIS system was pre-sented as a case study.

In addition to the 2 weeks of training, eachparticipating institution received a copy of all lec-ture notes, the critical hardware needed to con-tinue the project at home, and the followingsoftware, complete with documentation: AtlasGIS/DOS, Import-Export, and Arcview 2. An ongo-ing Internet-based discussion group for class or-ganizers and participants is providing a forum fordialogue and monitoring of participants’ progress.

Allen W. HightowerRobert E. Klein

National Center for Infectious DiseasesCenters for Disease Control and Prevention

Atlanta, Georgia, USA, and Guatemala City, Guatemala

APHA Session Features EmergingInfections

Emerging and reemerging infections will be thefeatured topic of a two-part session at the annualmeeting of the American Public Health Associa-tion, October 29-November 2, in San Diego, Cali-fornia.

The session, titled “Emerging Infections: Solv-ing the Mysteries in the Field and Laboratory,”will focus on the worldwide impact of new andreemerging infections from both an epidemiologicand a laboratory perspective.

Eight speakers from national and internationalhealth organizations will discuss the followingaspects of the public health threat of these dis-eases: public health strategies for controlling in-fectious diseases; social, geographic, ecologic, andenvironmental factors that have allowed thesediseases to spread; the growing threat of antimi-crobial resistance; the increased need for accurateand meaningful disease surveillance; and thechallenge to apply the latest laboratory technologyto rapidly detect and characterize new infectiousagents.

Martin S. FaveroNational Center for Infectious Diseases

Centers for Disease Control and PreventionAtlanta, Georgia, USA

News and Notes


Southeast Asia IntercountryConsultative Meeting on Preventionand Control of New, Emerging, andReemerging Infectious Diseases

An intercountry meeting to identify strategiesand approaches for tackling the problems of new,emerging, and reemerging infectious diseases inthe Southeast Asia region was held in New Delhi,India, August 21 to 25, 1995.

Nine countries (Bangladesh, Bhutan, India, In-donesia, Maldives, Myanmar, Nepal, Sri Lanka,and Thailand) participated. Experts from thesecountries, England, and the United States, as wellas representatives from USAID, DANIDA,UNICEF, the World Bank, and the World HealthOrganization (WHO) also attended.

Meeting participants expressed serious con-cern at the global and regional spread of new,emerging, and reemerging infectious diseases, es-pecially in the Southeast Asia region. Reports fromvarious countries emphasized that these diseasesnot only have worldwide health implications butalso can disrupt commerce and industry and setback important progress achieved in public healthduring recent years. The spread of these diseasesalso has major social and political implications.

Participants at the meeting underlined the im-portance of surveillance, prompt epidemiologic in-vestigation, and the build-up of adequatelaboratory capacities. The need for maintainingecologic and environmental integrity in variousdevelopmental activities was also emphasized.Member countries were called upon to immedi-ately review and strengthen capacities in epi-

demic surveillance and response and to formulatecountry-specific strategies and action plans to an-ticipate, quickly recognize, and rapidly respond tothe threat of emerging infections.

To ensure program sustainability, participantsstressed that strategies to combat emerging dis-eases should be an integral part of existing na-tional infrastructures, particularly infectiousdisease control programs, and should build on thecapacities that already exist. Four broad areas fortackling the challenge of emerging diseases wereidentified: strengthening communicable diseasesurveillance and response, strengthening the ex-isting infrastructure, capacity building for preven-tion and control, and applied research.

A total of 12 actions were recommended. One,for example, was that each country create a rapidresponse team to react to epidemic situations. Asecond recommendation was that countries de-velop linkages between their national referencelaboratories and WHO collaborating centers. Thiswould be to strengthen diagnostic capacities, fa-cilitate quality assurance, and promote nationalself-reliance in laboratory diagnosis.

Eight recommended actions for WHO to under-take were also enumerated. These included as-sessing and monitoring microbial susceptibility toantibiotics, and vector susceptibility to insecti-cides.

For the complete list of conclusions and recom-mendations of this meeting, contact WHO’s Re-gional Office for South-East Asia.

Samlee PlianbangchangWHO, Regional Office for Southeast Asia

World Health HouseNew Delhi-110 002, India

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