AD-767 964ANIMAL DISEASE SURVEY OF NAVASSA ISLAND,WEST INDIES

Richard J. Brown, et al

Naval Aerospace Medical Research LaboratoryPensacola, Florida

25 June 1973

National Technical Information ServiceU. S. DEPARTMENT OF COMMERCE5285 Port Royal Road, Springfield Va. 22151

S~oiaIReprt73-3

ANMAL DiISEASE'SURVEY OP NAVASSA ISLAND., WEST I NDI ESRtc~rdJ.Bror~,Ja~s .. Kupper, 'N .Hixson, John Bowman, Robert 0. Baker,

obart D..Doviis, A. F, Horne, and W. E. Briti

P ... I.. .I f-d V '1. u e 1 7

Approved for public release; distribution un~lrntled.

Unclassified

DOCUMENT CONTROL DATA- R & D

.ýtU I.d2SCUHfjI Y CkASI,,j It- l1ON

Naval Aerospace Medical Research Laboratory UnclassifiedPensacola, Florida 32512

N/A ____________

ANIMAL DISEASE SURVEY OF NAVASSA ISLAND, WEST INDIES

IN A . ............

Richard J . Brown, Lt Colonel, USAF, VC; James L. Kupper, Lt Colonel, USAF VC; W. C.Hixson; John Bowman; Robert 0. Baker, CDR, USN; Robert D. Davis; A. F. Horne, Captain,

_LISJM4.arW _ "L ri ti L,. LCaI[orslJ4SALŽLVC --- i11 - 0. 1 rý I 1il 140 0i.) 1. I-Aljj• i N l O fiflj

25 June 1973 .42.4 LL 21A .t i , U ~i ,ill A* U U11. tI, 0'l ,Ii ,, Uh f1lY I I UIIr•l I !l llt IuM?*

I...... .. Special Reoort 73-3

U, -,t II g r Im Ii FA 7-t 7 171A _t I Ii, , i .0,' 1

Apl loved for public: relecase; d istribution unl imi ted.

l) -..-... ---.. ... -.. -. - - - - - - - - - - - - --... .. . .... . . .... . .. . .. . .. .I'i I I I I l! ¢ I ,I •i i .I, *• I* ' I k, I I A . A l 1. 7 1 1

A,,II.I,,, ,U II H ,i , l

Navassa Island is locuited 180 25 minriet Cs north and 750 and zero minutes wesl and is tieclosest American possesslon to the United States Naval Station at Guantanamo Bay, Cuba. Theisland in uninhabited but has potential use to the United States if any sudden change in theCaribbean political Situation should occur. Necarly all overseas American possessions have beensurveyed for arrimcl diseases w th specicl cognizance toward zoonotic diseases.

The wild animals studied on Navissa Island included goats, ral, arnd several species of birds.Low I,:vels of mercury and DDT were detected in these animals. Radioisoto-re analysis of airmaIltissue revealed low levels of plutonium 238 and 239. Light microscopy examination of tissuedemonstruted sarcosporidiosis in wild rats, central nervous system degeneration in the goat compati-

ble with ca slow virus disease known as scrapie, oivian maularia and several pathogenic mr.tazoanparasiltes in various vital organs.

A contaci dermctlitis in man caused by the tree, Metopium toxiferum was identified. Serafrom goats, rats, birds and bats were nccalive for rabies aviF n -7hTTuerizia

_ _ _ IDD...... 1473. Uniclassi fied

.- . _

UnclaslfldSecurity Clauuiflcation

14. LINK A .INK B LINK CKEY WORDS

ROLE A WT ROLE WT M)LK WT

Navassa

Scrapte

Sarcosporidiosis

Plasmodiurn

DDT

,Radioisotope

DD, 1OR. 1 4 7 3 (BACK) Unclassified(PAGE 2) / /Secu.rity (- niiclrk to

Approved for public release; distribution unlimited.

ANIMAL DISEASE SURVEY OF NAVASSA ISLAND, WEST INDIES

Richard J. Brown, James L. Kupper, W, C. Hixson, John Bowman, Robert 0. Baker,Robert D. Davis, A. F. Horne, and W. E. Britz

SPECIAL REPORT 73-3

Approved by Released byAshto S aye-F,'e" M.D. Captain N .?-A'lleach, MC, USN

Assis: int for Scientific Programs Officer in Charge

25 June 1973

Naval Aerospace Medical Research LaboratoryNaval Aerospace Medical Institute

Naval Aerospace and Regional Medical CenterPensacola, Florida 32512

C///

SUMMARY PAGE"

THE PROBLEM

Navassa Island is located 18' 25 minutes north and 750 and zero minutes west andis the closest American possession to the United States Naval Station at GuantanamoBay, Cuba,. The island is uninhabited but has potential use to the United States if anysudden change n the Caribbean political situation should occur. Nearly all overseasAmerican possessions havc been surveyed for animal diseases with special cognizancetoward zoonotic diseases.

FINDINGS

The wild animals studied on Navassa Island included goats, rats, and several speciesof birds. Low levels of mercury and DDT were detected in these animals. Radioisotopeanalysis of animal tissue revealed low levels of plutonium 238 and 239, Light microscopyexamination of tissue demonstrated sarcosporidiosis in wild rats, central nervous systemdegeneration in the goat compatible with a slow virus disease known as scrapie, avianmalaria and several pathogenic metazoan parasites in various vital organs.

A contact dermatitis in man caused by the ftee, Mefopiurn toxiferum was identified,Sera from goats, rats, birds and bats were negative for rabies and avian influenzia

ACKNOWLEDGMENTS

Consultation regarding this study was provided by the Armed Forces Institute ofPathology . The authors wish to acknowledge the technical assistance of Mrs . KathrynHenry, Mr. Alvin Armstrong, Mr. Robert Barrett and the support of Mrs. Janelle Key.The authors are also greatly indebted to Chief Hospital Corpsman Howard Beal, Photo-graphers Mate First Class S. F. Griswald and Photographers Mate Third Class A!Whittenberg for their technical assistance in the field.

It is a pleasure lo offer acknowledgment to Dr,. Donald Hinkle, USPHS, Perrine,Florida, for the insecticide analysis; to Dr. Jerry Winkler, Rabies Unil-, CommunicableDisease Center, Atlanta, Georgia for serologic studies; to Dr. James Prine and Mr.Evan E.. Campbell of Los Alamos Scientific Laboratory for the radioisotope analysis; tothe officers and men of the USS Detroit and LTJG Berry Merrill fkr the transportationarrangements in the Caribbean; to Dr. A,, E. McKee and Dr. R, L. Beaudoin of theNaval Medicil Research Institute, Bethesda, Maryland for plasmodium consultation;to Dr. J . Ralph Lichtenfels of the National Animal Parasite Laboratory, Beltsville,Maryland for nematode consultation; and to the University of West Florida BotanyDepartment for tree identification.

*The animals used in this study were handled in accordance with the "Principles

of Laboratory Animal Care" established by the Committee on the Guide for LaboratoryAnimal Resources, National Academy of Sciences, National Research Council.

S.~

"Commander R. 0. Baker is Public Information Officer, Pacific Missile Range,Point Mugu, California. At the time of this study he was on the staff of the Chief ofNaval Air Training, Pensacola, Florida.

Dr. Robert D . Davis is Pathologist, North Miami Hospital, Miami, Florida. At thetime of this study he was Chief, Department of Pathology, Naval Hospital, Pensacola .

Dr. A. F. Home is Captain, U. S. Public Health Service and is in the Office ofthe Chief Medical Officer, U. S. Coast Guard, Washington, D.C. At the time ofthis study, he was a resident in aerospace medicine at the Naval Aerospace MediculInstitute.

Dr. W. E. Britz iz Director of Veterinary Services, U. S. Air Force Hospital,Clark Air Force Base, Philippines. At the time of this study lie was Chief, VeterinarySciences Division, NAMRL.

- -- * i

.• ,V

INTRODUCTION

Navasso Island is located at 180 25 minutes north and 750 and zero minutes westand lies in the windward passage about 32 miles to the west of the western promontoryof Haiti. It is the closest American possession to the United States Naval Base atGuantanamo Bay, Cuba.

The United States has had possession of this island since July 1857. It is accessibleby water with considerable difficulty because the shoreline is a perimeter of white cliffsup to 75 feet high. The island is deserted and has no human inhabitants. The majorityof the ":reaturcs living there are goats, cats, rats and birds . Dogs were reported to beon the island running wild but none were observed in our study. Various branches of theUnited States government have published pilot studies, and in some cases detailedtreaties, on animal diseases in American overseas possessions. The main purpose ofthese surveys is to detect and, if necessary, eliminate diseases of animals transmissibleto man and when appropriate reduce and/or eliminate animal diseases of economicimportance. As far as the authors were able to determine a study of animal diseases hasbeen accomplished on all American overseas possessions except Navassa Isiand.

A National Institute of Health National Library of Medicine Medlars review of theliterature revealed that thc had not been even a pilot survey of animal diseases onNavassa Island.

An American visitor to Navassa in 1969 reported that during his visit foreignnationals slaughtered some of the goats on the island for food . He indicated thi wasa common occurrence by these foreign nationals. The presence of animal diseasestransmissible to man would pose a danger to anyone obtaining food on this island.Absence of residual latent animal diseases transmissible to man oi Navassa would absolvethe United States of liability should foreign nationals and/or U . S . citizens contract orclaim to have contracted such diseases while conducting activities on Navassa.

PROCEDURE

Briefly, the work was accomplished under field conditions and consisted of obtainingboth mammal ian and avian specimens; physical examination of these animals ; andremoval of biological samples from these aninials and processing of such samples . Thisincluded freezing of scra and fixing of major body organs in fixative fori light micro-scopic examination. The specimens obtained on Navassa were submitted to variouslaboratories for processing . Tissues for I ight microscopy were processed in our Pensacolalaboratories.

A randomly sampled pilot animal disease study as this eequires the capturing, trappingand restraining of animals to obtain medical samples fr laboratory analysis. This wasaccomplished in se,'era l ways. Large rats were trapped it) live animal traps. These traps-,ere essentially ba ted cages that closed when the animal entered lhe cage. Ten trapswere set in equidistant directions from thei lighthouse, which is located at the highestpoinrt of the island, cnpproxi mate I y two hundred fifty feet above sea level

........ .....

Two large wild gray rats were trapped during the five-day stay on Navassa. Bothwere trapped during the night, reflecting the nocturnal habits of these animals. No onein our group reported seeing rodents during the day.

The standard capture gun was used to obtain larger animal specimens. This devicefires darts which injects tranquilizers into the animal . Ketamine was employed as thetranquilizing agent. The single feline specimen was obtained using the tranquilizer gun.One avian specimen was obtained in this manner, The intent with regard to the caprinespecimens was to utilize this same tranquilizer dait device. However, the franquiliz,.rtakes up to sixty seconds to render a goat immobile. The Navassa goats, being well-adapted to rapid travel over the rough, jagged, pocked terrain, would quickly disappearin rapid flight into the thick underbrush and would be well out-of.-distance when thetranquilizer took effect. Keeping track of these rapidly moving, frightened animals wasdoubly difficult as it was necessary for us to devote most of our attention to watching ourstep so as ro avoid personal injury. Consequently, the capture gun method was ineffec-tive in obtaining caprine animals. On the third clay it was decided to sacrifice ten goatsby two teams of two or three men. Each team utilized a .30 ccilber M-1 carbine tocollect the caprine specimens. The teams prearranged diverc nt hunting areas to avoidany crossfiring.

A veterinarian or physician was with each team and would perform the necropsy inthe field, collecting major body orgar's and sera which would immediately be relayedback to the lighthouse building for processing. The tissue was fixed in ten per centneutral buffered formalin and the sera was centrifuged and frozen. Additional samplesof tissue were frozen in dry ice fo, insecticide, pesticide, heavy metal and radioisotopeanalysis.

Perirenal fat from the mammals and rnesenteric fat from the birds was frozen forinsecticide and pesticide analysis.

The major avian specimens present on Navassa included the Man-of-War, Fregatamagnificens, and Red-Footed Booby, Sula sula. These specimens were obtc~ineJTy--t7Tetwelve gauge shotgun method in a larg-e ortigated clearing north of the lighthouseThis area appeared to be the beginning of the construction of a shcf field- landingarea.

Two investigators were placed oil either side of the clearing with shotruns and athird in the center with 10cc syringes, blood tubes, and slides. The firing o' one ofthe guns would attract thie curious Man-of-Wa' birds as they would approach the area,they would be downed while traveling in a direction and velocity such that they wurldfall in the general area of the investigators. Eight to ten cc of blood would b? drawnwhich was transferred to the blood tubes and allowed to clot. Blood smears wure made,placed in a plastic slide box and stored in the refrigerator at base camp. The standardtwo-slide method of producing blood smears was utilized. The smears were stainedwith the Gienisa stain upon our return to Florido. Avian blood was centrifuged andfrozen in a manner similar to the goat blood. The birds were carried back to tle rooflessadministration buii ding where a pathologist completed the necropsy

2

r-.

I

The bird remains were disposed of by dropping them down a 30 x 30 x 4-footdeep shaft near the lighthouse. While dropping these avian remains in this shaft at

dusk, several bats were observed leaving the shaft. Apparently they resided there

during the daylight hours immediately under the building constructed over the shaft.

This provided us with the manner of collecting bats for rabies studies. Several mist

nets were spanned across the shaft opening the next day. These nets are large 2 .4 by

12 meter nets with a mesh of 36 millimeters, giving them the appearance of a very large

woman's hair net. The mesh is so fine thai birds and bats are not able to determine its

presence; they fly into and become entangled in these nets.

Rain fell the first night the nets covered the shaft and no bats were caught. The

next night three bats became entangled in the ncts and they were captured and frozen

for submission to the Rabies Laboratory.

Aquatic animal specimens were difficult to obtain by the usual methods. Onecrovelle jack was obtained with a spear gun.

RESULTS AND DISCUSSION

The results will be presented by generally considering findings of each class ofanimals surveyed . Within each animal grouping will be sub-headings as appropriate.Discussion of pertinent points will be included with the associated results to provide amore meaningful correlation of pathologic entities and their significance, such as lifecycles, etc. Chemical, radiological and serological tabulaHons will be consideredseparately.

I welve random samples of liver, kidney and mesenteric fat from bird, goats, andfish were analyzed for mercury, All contained less than one microgram of mercury pergram of tissue. Radioisotope analysis of harvested tissue from the animals is listed inTable I . Results of ir-,ecticide and pesticide analysis of mesenteric fat samples fromgoats and birds are listed in Table II .

Background Radiation Measurements

Background levels of beta and gamma radiation in combination and gamma radiationalone were measured at selected locations on Navassa Island using a portable battery-operated AN/PDR.-27C'( Radiac Set. This instrument, serial number 3910, had beencalibrated by the Naval Electronic Systems Command, Southeast Division, RadiacRepair Facility on November 16, 1970 and certified to be ± 20 percent or better of itsdesign specifications.

Immediately before the field trip, battery condition was checked and referencesensitivity readings established for the 0.5 and 5.0 milliroenlgrens per hour scales usinga MX-1083 13/PDR-27 radioactive test sample is input. U .on setup of the instrumentat the Navassa Island field rite adjacent to the lighthouse, the same procedure wasrepeated to verify proper operating status for the instrument.

3

With the instrument set to the 0.5 millitoentgen per hour range (maximum sensitivity),and using the built-in meter as visual reference in conjunction with simultaneous headset monitoring, sample background rad'ation data were collected in a variety of locationsimmediately surrounding the lighthouse. In all cases, the background radiation, betaplus gamma as well as gamma alone, remained at a normal low-level of approximately0.02 milliroentgens per hour.

Though the rock formation in the vicinity of the lighthouse was representative ofthat found elsewhere, the above data were derived solely from surface measurements.For this reason, further measurements were made along the railroad bed cut into therocks below the liqh•house which was directed toward Lulu Bay. Sample data werecollected along the subsurface walls of this cut, as well as from various large piles ofrocks that had been excavated from the area. Again the radiac set indicated thepreviously mentioned low-level bacl<ground throughout these areas.

A last subsurface test was performed in the large pit found adjacent to the light-house. Using a stop watch calibrated in seconds to time the f'ee-fall of a rock droppedinto rie pit, it was estimated that its bottom was approximately 275 to 300 feet belowsurface level . To collect background data along one vertical wall of thiF pit, a 200

foot coaxial cable was tied to the radiac set and used to lower the instrument to thefull length of the cable. This coaxial cable also served to eiectrically extend theinstrument headset circuitry so 'hat audible monitoring of background level could bemaintained during the descent., The instrument was lowered two times, once with theprobe in the radiac set well with its shield in place and once with the probe placedoutside the well and taped to the side of the instrument with shield removed . Thisrepresented the gamma and beta plus gamma, respectively, measurement capability ofthe instrument. Again the headset count stayed at a frequency comparable to thatobtained for the previously described background. The only disturbance tionradiation"related) encountered was the hurried departure of several bats as the instrument was firstlowered into the pit through the central hole of the measurement staticn.

Avian Diseases

Blood Parasites

A gamma stained smear from one Man-of.War (Fregata magnificens) bird demon-strafed an intraerythrocytic protozoan parasite (5). -B--ooa-smiears Tr-om-several otherbirds were within normal limits. Figure 1 illustrates a microgametocyte in the cytoplasmof an erythrocyte.

Microscopic examin:jtion of the tissues from this case revealed hepatic malarialpigment. There was also a mild focal chronicrmyocarditis.

Plasmodium is one genus of the s:veral intraerythrocytic protozoan parasites foundin birds. Haemoproteus, a close relative, does not undergo asexual reproduction incirculating erythrocylos as does plasmodiumr. Consetuently plasmodium can regularly betransmitted from an infected animal to a susceptible host by injection of infected blood

4

or by a bloodsucking insect vector. Kikuth reported the German thrush to be the hostfor Plasmodium circurnflexium, while Levine and Hanson reported it in a Canadiangoose (12, 13).

The life cycle of Plasmodium circurnflexium reportedly involves all stages occurringin the circulating blood and the various stages tend not to displace the nucleus of thehost's erythrocytes (4).

The life cycle of plasmodium in the Man-of-War bird is uncertain. Vectors ofavian malaria are generally conceded to involve the Culex and Aedes mosquitoes.It is unnecessary to dwell here on the general life cycle of aviarTmnHmaria as suchinformation is available in nearly any text of protozoology.

Because of time limitations, the survey of Navassa was restricted to vertebrates.No attempt was made to identify the mosquito population. Mosquitoes were noted to bepresent near the potable water cistern in the old lighthouse administration building atopthe island. Hoperully the Navassa mosquitoes can be identified on tbe next visit to theisland.

A proventricular pacrasite, identified as belonging to the genus Tetrameres, wasfound in the Reddish Egret, Dichromanassa rufesceus (Figure 2). Bof tht-e fema-le andmale forms were seen in microscopic sections. Several cross sections of the gravidfemale demonstrated many embryonated ova . The males were in the lumen of theproventriculus while the female is buried in the glandular wall. Little inflammatoryresponse is elicited by the female.

The life cycle of this parasite requires grasshoppers, locust, crickets, cockroaches or

water fleas as intermediate hosts, After the bird ingests an intermediate host containingan embryonateJ larvae, the larvae migrate to the proventriculus and develop into adults.This parasite is most likely Tetrameres fissispina which is reported to occur in wild aquaticbirds (21).

Trenmatodes oi flu'-es of the kidney were found in two Man-of-War birds (Fregata

magnificens). The flukes were distending the collecting tubules with a subac-te.

-nl ammatory response surrounding the dilated tubules. The flukes were identified bytheir single dorsal sucker (Figure 3).

The intermediate hosts of avian kidney flukes are land snails, most commonlySubulina actona (4). No land snai Is were identified by members of the group . Birdsbecome infected upon ingestion of infected snails containing encysted rnetacercariae.Avian nephritis caused by trematodes has been reported in Puerto Rico and South Americapreviously (A). These parasites are placed in the Genus Tamerlania.

Nematodes, or round worms, recovered at autopsy from the Fregata magnificens onNavassa included the genus, ContracOecum, probably species grcVuTosm (ord..Ascaroidea). The life cycle of Contracoecum is not well known. Larval forms occurin water crustacea (21). Contracaecum are found in other water fowl such as duck,geese, etc . This parasite elicited a mild hemorrhagic enteritis in this Man-of-War bird.

5.

. .

A 2 cm bladder worm was found of necropsy of a Fregata magnificens between theright and left lobes of the liver (Figure 4). Since the-dTi-o-fT 'e•se---rJ-sis tropicalsalt water fish, it is probably an intermediate stage of a tetraphyllidean or pseudo-phyldidean, fish tape worm. The life s of these cestode species has not been workedout, but is believed to also include a copepod.

A cestode of the genus Hyamenoleýp_ s, probably Hymenolepis comressa, was recover-ed from the duodenun, of arotherFre•ata__rna_.rrficens. The developmental cycle of thisgenus is unknown but heavy infections can lead to a general debility.

A Reddish egret demonstrated an early mild case of simple or colloidal goiter.Several acini are moderately distended arid filled with colloid and the acinal e)ithelrumis thiinned. No interacinal connective tissue increase was noted. Goiter is ge ierallyassociated with a deficiency in iodine although other factors such as calcium ar.d sodiumchloride imbalance, amino acid and co-enzyme. deficiencies, impaired iodine uptakeand utilization are also believed to cause goiter (10). Generally sea water is believedto contain adequate amounts of iodine and since the Navassa avian biota consume almostentirely fish, an iodine deficiency in the animals would be surprising , However, Bakerand Lindesy reported goiter in animals due to excess dietary iodide (3). i\s is mentionedelsewhere in this report, a wild feline captured on Navassa also had a simple orcolloidal goiter,

The Navassa ground dove, Columbigaiina passerina, contained numerous amorphousbirefringent crystals in the liver sinusoids. They were identified as calcium carbonatecrystals but their source and significance has not been determined.

One Fregata magnificens had a fibrous thickening of the valves of the heart, knownas endocar IdT1`os". --7h- cJJusps vere shortened and thickenea and the surfaces of the valveswere smooth and glistening. Microscopically, there was no evidence of an inflammatorybasis for this condition. Lesions such as this are probably due to excessive cardiac workload. This bird also had a diffuse, mild, suppurative hepatitis. Special stains revealedno specific etiology.

A contact dermatitis was developed by seven of the eleven mer..,ers of the teamduring the week long stay on Navassa . The inciting agent was Ihe milky, acrid,resinous sap from the Florida Poison tree, Me'topium toxiferum (Figures 5 and 6). Thistree had a smooth dull gray bark with spher1~T'c-m•-T-ooti-green poisonous fruits about one-half inch in diameter. Team members came in contact with this tree sap while enlargingthe landing area for the helicopter. Twenty-four hours after exposure the contactedarea of the skin developed erythematous confluent vesicles approximately 2-3 mm incdiameter. Several had broken down with release of clear serous fluid . These lesionswere primarily on the flexor aspect of forearm and the wrist (Figure 7). They weremarkedly pruritic and moderately painful . There was no regional lymphadenopathy orsystemic symptoms. Smoke from burning Metopium toxiferum is also reported as irritatingto the sl<in, eyes, and lungs (2). In an excellent Botanical summary of Navassa it, 1959,Proctu r mentioned Metopium taoxiferum as one of the frees he identified (17),. 0',e

6

Navassa lighthouse keeper was incapacitated by a tree contact dermatitis in 1928 andhad to be relieved from duty. Presumably, the above mentioned species was responsible(8).

The existence of bats on Navassa Island was first reporlt d in 1928 (8). Thesemammals reportedly inhabitaied several small caves near the center of the island . Thebats were identified as Artibeus jamaicensis,a fruit eating species of the West Indies(Figure 8). Sera from these bats were negative for rabies and type A influenza.

The goats examci,,ed utilizing light microscopy on Navas.a are interesting from astandpoint of what was found as well as what was not found. These animals wereabsolutely free of the ubiquitous pulmonary anthrocosilicosis seen universily in man andanimals in areas of even sparse population. This is an inhaled pigment, undoubtedlyfrom combustion products of automobiles, factories, etc. The absence of this pigmentis indicative of the lack of air pollution in this area of the world (19),

The livers of all of the goats examined contained small foci of extramedullaryhematop( iesis. In the adult animal, this usually represents irmpaired ability of the bonemarrow to produce blood or the presence of a condition causing excessive destruction orloss of lood cells. Exposure to ionizing radiation and some diets will cause this condi-tion. The most likely cause of this condition in wMld goats would be chronic anemia dueto intestinal parasitism. How,•ver, the fecal egg count from these animals was low.Tissues from these animals revealed no evidence of infectious hemolytic diseases. Plantscausing hemolytic anemia and thus extramedullary hematopoiesis include onions, Helio-tropium, Senecio and subterraneum clover but none of these plants were identified onNavassa. Perhaps one of the usual Navassa dietary plants of these animals causes ubone marrow depression.

The dermal toxicity of the abundant Metopium toxiferum is discussed elsewhere inthis report. When fruits are consumed from trees t-a-t caucontact dermatitis, they

frequently will cause ulceration of the intestinal tract (15). Leaves from this tree werefound in the stomach of the Navassa goats and it can be presurmed that the fruits arealso occasionally consumed. Therefore, it is possible that the extramedullary hepatichematopoiesis in the Nuvassa goats is due to chronic blood loss resulting froom intestinalulceration due to ingestion of foliage and fruits of the Metopium toxiferum.

Caprine central nervous system changes included focal thickening of the meningiesby cap cells. These cells are normal inhabitants of the muningies and occasionallyundergo hyperplasia, causing meningeal thickening (Figure 9). In man this is considereda norrlal aging change (9). This condition has been reported only once -,eviously inanimals (6).

Other changes in the caprine central nervous system are spongiosis of gray mattervacuolization of neurons and loss of Purkinie cells in the cerebellum (Figures 10, 11,and 12). These changes are reminiscent of a slow virus disease of goats and sheepknown as scrapie . Similar nriuropathologic changes are seen in man in New Guinea ina disease called Kuru.

7

Scrapie is a non-febrile chronic disease of sheep and goats characterized clinicallyby pruritis and abnormalities of gait (16). It has a very long incubation period and iscaused by a virus-like agent capable of withstanding the usual virucidal procedures. Theincubation period may be as long as three yc.ars while the average period is 18 to 20months. The clinical signs are an intense pruritis, muscle trenors aid marked abnor-malities of walking as well as severe emaciation. Persistent r.ibbing causes loss of hairand wool over the areas along the back, hence the name scrapie. The animal may shakeits ears severely causing a hematoma. Great interest has been shown in the diseasescrapie in the past few years because the histopathological lesions of scrapie are identi-cal with the presumed temperate virus infection called Kuru in man in the New Guineahighlands. This disease is fatal in man. In scrapie as in Kuru it is suspected to be aviral meningocephalifis. However, very little in the laboratory findings or its epi-demiology has been discovered to support a suspicion that it is an encephalitis. In bothdiseases there is nothing in the neuropathology picture to suggest an acute infection. InKuru, the epidemiological pattern suggests some genetic expression of the disease. Inscrapie in animals, however, the population restriction and geographical isolation of theanimals involved usually is not available. In the case of Navassa Island, however, thiswould not be true.

Generally neither disease shows a febrile response. There is insufficient perivascularcuffing of the spaces of Virchow-Robin or other neuropathologic reactions to suggest anacuWe infectious etiology. Kuru has been associated with extensive cannibalism but thishas been dismissed as unlikely (11). Cannibalism among goats or sheep also is essentiallyunheard of. While the exact etiology of Kuru still is in dispute, Hadlow in 1959 pointedout that in animals the susceptibility to the scrapie virus is generally accepted as beinggenetically determined. Inbreeding of animals on a restricted island could well accentu-ate the genetic susceptibility to scrapie . Scrapie in sheep and goats is probably bestconsidered a chronic degenerative disease of the central nervous system and caused byviral agents with prolonged incubation periods.

Figure 13 demonstrates a caprine neuron containing a rectangular, deeply basophilic,cytoplasmic structure. The nucl ;. of this rneuron is not visible and neuronal nuclei infthis or any other capri ne from Navassa does not resemble this stru.)cture . Autopsies of

V ten Navassa goats revealed considerable amounts of ingested periwinkles, Catharcanthusroseus . This plant, harvested from Madargascar, is the source of the chemto-erapeuticagentVincristine used cis an antileukemic drug. Schochet reported similar structures inneurons of rabbits administered intrathecal Vincristine (18). The possibility that ingestedperiwinkles can produce change,; similar to Vincristine is an interesting one and needsfurther study.

Several goat lungs revealed small inflammatory cell nodules comprised of lympho-cytes, plasma cel Is and eosinophiles (Figure 14). Special stains for bacteria and fungiwere negative. This subacuv• granuloma is probably due to the lung parasites,Dictyocaulus filaria . This parasite occurs in the bronchi ot sheep, goats and other wildruminants. Di-ctyocaulus filaria has a world-wide distribution and in large numberscauses serious losses. The eggs may hatch in the lungs but are usually coughed up andswallowed and hatched while they pass through the alimentary tract of the host. The

8

first stage :arvae are passed in feces. The three stages do not feed but exist on foodgranule: in the intestinal mucosa. The larvae require moisture for their developmei.rand become infective in six to seven days. They can yvthstand moderately dry conditionsfor a few days. The animals are re-infected orally. Intie arvae penetrate into theintestinal wall witlhin three dcays und pass via the lymph vessels to the mesenteric lymphgland where they develop and perform their third ecdysis about four duys after infection.In the fourth stage larvae the males and females can be distinguished . The worms nowpass via the lymph and blood vessels to the lung where they are arrested in the capillariesand break through into the air passages. Development to maturity in the host lungs takesabout six weeks. The worms live in the small respiratory passages where they suck bloodarid irritate the mucosa. This produces a catarrhal bronchitis. The inflammatory processspreads to the surrounding peribronchiolar tissues and the f.xudate frequently passes backinto the bronchioies and alveoli causing atelectasis. Pneumonia can be set up if bacteriaare present in large numbers , The most effective prophylaxis against this condition iskeeping the animals off infected grounds.

Two large aggressive rats, Rattus sp. were obtained on Navassa Island. Cysts ofthe parasite Sarcosporidia were Found• in-the masseter muscle uf one of them.. Sarco-

sporidiosis is familiýr to veterinary pathologists as an infection of striated muscle by theorganism of the genus Sarcocystis. It is much less familiar to the human pathologists asthere have been only 13eI'oumented reports of this condition in mani where it isusually an incidental finding at autopsy (7), These organisms in man are known as

SSarcocystis lindemanni.

The sarcosporidic life cycle is not completely known. It is commonly found at postmortem inspection of animals slaughtered for food, mostly cattle and sheep. Since it isnot known whether or not its life cycle involves man, all infected meat animals arecondemned for human consumption. This represents a loss of several million dollarsannually. What is known about the life cycle was first demonstrated by Theobold Smithin 1901 using the mouse . Smith demonstrated that mice could be infected with Sarcocystismuris by feeding the feces of other mice infected with S. muris (7). The exact 'it-nIflio-•doTt-ansntission to man remains obscure but based on the rTginal work by Smith, it isprobably that man is infected by oral ingestion with fecal nmaterial containingSarcosporid ia muscle cysts. Complete passage of the parasite through the intestine may6-a necessary part of the developmental cycle (21). There appears to be no inter-mediate host or insect vector. The infective stage or trophozoite probably passes throughthe intestinal wall, into the blood stream and lodges in various striated muscles.

The skeletal muscle of the head of one of the rats contained numerous Sarcosporidialcysts (Figures 15, 16, and 17). The sarcolemma of the infected muscle is displaced and,as in trichinosis, there is no inflammatory response.

A close relationship between Sarcocystis and Toxoplasma has been demonstrated in

that both react with cytoplasm modlTyng b-•ibody T n Jte-'S'a-- in-Feldman dye test. Crossreactions between the two organisms are common. This serologic relationship ofSarcosporidia to Toxoplasma and the current publicity regarding fetal toxoplasmosis in

9

Ia

muo is also worth consideraficn (14). The coccidia of the cat has been recentily shownto be texoplasma. Futur, studies may also show that sarcosporidiosis is still anothervariant of Toxoplasma gondi

The importance of this zoonotic organissm on Navassa is the possibility of infection ofany food prodicing animals that might be raised or are already present on Navassa . Thelighthouse keepers in years past frequently consumed goat meat for its protein content.While no sarcosporidlal cysts were identified in our caprine tissue, Navassa goatconsumption should be discouraged in the future,.

The occurrence of a disease, whose life cycle is not completely clear, on a small-island provides an excel lent oppurtuni ty for sorneone to do further work on the life cycle.Extensive microscopic examination of the muscles of additional goats and birds shouldalso be carried out.

A nematode of the genus Gongylonema was found in one rat from Navassa.Nematodes of this genus have lTe j)7erf- in many animals inclucding nonhumanprimates (1) and man (20). This is another one of the parasites that is associated withmalignant tumors in rats. The adult worms live in the epitheliurn or submucosa of theesophagus, Within the epitheliurn they are found lying in a zigzag fashion (Figure 18).Their life cycle is indirect, the intermediate host being clung beetles and cockroucheswhich ingest eggs fr'om the feces of the definitive hosts.

Additional sections of the terminal esophagus and upper stomach of one rat revealedeggs with scolices t/pical of tapeworm eggs. The tapeworm, Tenia teniaeforrnis,(Bat'sch, 1786) which as an adult tapeworn occurs in the smal int)estine in tlie cat and -other related carnivores has been identified from Navassa animals. The bladder worm isknown as Cysticercus fasciolaris, also known as Strobilocerus fasciolaris (Figure 19).The stage MIha%"occurs In--TfThe-'-Fi-,-r is tf.e strobi locercus .7"Oec_,-stPc-ei'rcus is fairly commonamong rodents, especially rats and tn;ce and in the liver is found as a large ivory whitecyst. The larvae are peculiar as they a,e comprised of an extruded scolex followed bya strobila which is already segmented and terminates in a relatively small bladder sothc t the whole larva looks Ii ke a smac II adult tapeworm. When the eggs are shed insegments in the cat's feces, they are ingested by the rat. In the rat's stomacili theoncospheres are released from the eggs and reach the liver of the rodent as an inter-mediate host and grows rapidly to become the cysticerci and they are infective 30 dayslater. Initially these larvae appear to be relatively harmless to the rat, even when theyoccur in large numbers, but they induce a nilglignant scacoMra i1 ",1. liver some tWL'to fifteen months after infection . This parasite I,- been , :uely studied because of itsability to produce fatal cancer. It appears that c,<tn strains of rats are much moresusceptible/ to the development of these tumors than are others . Furthermore, immunity

in rats against this parasite may be induced by more than one method such as injectionsof extracts of either the larva or the adult worm . Immunity developed in this way persistsfor considerable periods of time and may be passively transferred . Where cats and ratslive together this disease usually is seenr. Descendants of cats left by tile lighthouse

10

keeper on Navassa Island in 1929 still live in the wild and presur.ably are the primaryhost for this tapeworm while the rats are tile intermediate host containing thestrobi locercus.

Multiple granulomas were found in the mesenteric and internal iljac lymph nodes,spleen, liver, urinary bladder wall, maxilla, mandible and in multiple skin foci of arat. The center of these .gtnoulomata contain large pools of polymorphonuclearleukocytes harboring nun>.. , sulphur granules (Figures 20 and 21). Special stain fortuberculosis and mycotic c,:' .. nisms were unrewarding. However gram stains revealedgram positive cocci within these sulphur granules typical of staphlococcus. Thiscondition represents a delicate balance between the staphlococcus and its host, whereneither can overcome the other. It is known as botryomycosis. By careful dissectionand meticulous gross examination a nematode parasite was found in association with oneof these botryomycotic lesions. This parasite was identified by a parasitologist as amember of the order Spirurida, family Thelazildae and either the genus Rictularia orPterygiodermatides. It is probable that the extra-enteric somatic migratfTonorthsnematode waste-cause of these grunulornaious murine lesions. Species of the genusRictularia that have been reported to infest rats include cristata, ma.gna, o2!'Lojpectine__aa,an-dw rtoni.

The nematode, Mastophorus muris, was recovered from the intestinal tract of oneof the Navassa rats. --'r 5F •a t he 'at are the definitive host for this parasite withthe flea as the intermediate host.

Only one Fells domesticus was identified and examined on Navassa Island. Simpleor colloidal goterwasdTagnsed in this animal . The thyroid acini were markedlyenlarged, distended and filled with colloid (Figure 22). The usual cause of this conditionis iodine deficiency; the aspects of this condition on an island are considered earlierand the same comments are applicable here.

Feline multiple granulornotous nephritis is probably due to extra enteric par'asiticmigration (Figure 23). Special stains on these lesions for bacteria, mycotic organismsand tuberculosis were unrewarding. A mild grantdomatous glossities in the feline wasconsidered as caused by foreign body penetration (Figure 24). Special stains on thisorgan were also unrreward' mg.

DISCUSSION

Discussion of the pertinent points of ecach diseease entity was included under resultsto achieve a meaningful correlation of pathologic entities and their significance. Onlyadditional general comments will be made here.

The isolation of the island from the outside world suggests that the conditionsieported have been here for many years. The authorized visitors number only ca dozenor so u year arid these are usually active duty military and/or scientific groups,probably with above average health status.

11

Most of the Navassa birds are classed as non-migratory although avian travelthroughout the Caribbean is probably common . It is not impossible that a passinghurricane could deposit small rodents and micro-organismns heie.

The rair. nights precluded bats from leaving thei: daytime roost;ng places andthis diminislhed the total number of 1,.rvested bats. rhe negat'ive report of bat rabiesshou.J no; be !aken to mean that trie disease does not exist on this island in the bctpopula ti on.

Metazoan parasites comprised several of the disease conditions, a common findingin tropical areas.

The DDT content of the animal tissue was higher than would be expected, TheCoast Guard has maintained jurisdiction over Navassa since 1916 and so far as can bedetermined, the island has never been sprayed with this insecticide.

RECOMMENDATIONS

The purpose of a i0lot study such c's Ihis is to uncover further areas of study.Sarcosporidlosis was not seen in the caprine population, however this zoonotic parasiteoccurs most often in the mnasseterf, diatphreim and intercostal muscles, Subsequent visitsto the island should concentrate on this entity.

Feeding of harvested Navassa Sarcosporidia to experilmental animarIs, thus repecrtingsome of the research performed before could determine if tf ese protozoan are of adifferenr virulence than usually expected. Plasmodium chicumflexum is commonlyfound in more northerly latitudes. Since it is not l<owr wha-t genus of mosquito isinvolved in the life cycle of this malarial disease in the tropics, collection andidentification of mosquitos would be worthwhile during the next visit.

The possibility that periwin!'ole ingestion in goats may cause central nervous sytemnchanges should be explored further. The neuronal changes described in this paper urereported in the ganglia of other experirnentar animals ancd future caprine autopsies on,Navasscr should include gangl ia examination.

Another possibility involves replanting of the Navassa periwinkluI.s at some studycarea in the southern United States and feeding these to various animals in search ofthe vincristine changes reported (18).

l:iially any return to Navassa should collect as many large rodents anti bats as

possildlu Bats are excellent sentina Is for rabies and the Na'.'assa rats are apparentlyafflicted with an unusually large number of pathologic entities.

The ruggedness of the terrain andt the year-round heat make collection of samplesand specimens from the animals a difficult and tim.-consuming task . These fieldenvironmental factors greatly extend the tinie required to perform laboratory procedureson Navassa. Further disease surveys on Navassa should be extended to approximatelyten days

12

Il'I)I( I

I)isii te(','rat iol pe E lM u Ite l permllpe of luton ii lluml 238 anud 239 from antnimal iti 41su11s fromu Naasst i slan d

I)sintegraltions per nillill" per samle

1,hilb lilillio i 238 Plihioniii 2:19

J acklli , Aver 2() i.() 1F2 0.008

Goiat No, 6 1 lver 00 0.03o 0,060

Goat No. 101 Kidniey 20 0.000) 0.159

(;oil I -N III Kidlic'1 0.0 11 0,072

Got No., I IKidniey 29 0.004 0,000)

Aviaini I(Frigaite) 14 K Widlie'y 211 0.0)12 0.000

Goil 'No, 5 I illi 226 0.000 (),013

Avian (FIriglte) 13 Liver 113 0,0(9 0,017

Cat I I Li ver 9 0.0040 04,4000

(;lit KidIney 33 0.00(0 0.000

Catit I'ling 1 .01111 0,0811.

Avillii (Galltl) I I,ivvr ,1 0.(00 0.000

Aviti, (Ginet) -12 i'kloWn 1i 0).00(4 01.013

l (1' 14 Kidneh 2 0.002 U.002

1* Gotldi 1111.II L iver 0i1l 0.008l 0.004.

Aviall ( rIiillte) IAr 21 0,0 17 0.(M I

AVilll ( 'igilkt,') Iiver 20 ( .,0315 (,0411

Aviii (Frigatle) Iiver 121 0.04o (4.(i) I

Goal liver 7) 0.t 0 11 (0,(0 14

Goaut Kidnley 212 010241 0.0 181

Goat I ,ivr .139 (4. 0 (".08 111

Goat 170lil 00.2 0.03 I

i.. fll lil ' lil, i lba tol. i lld V ti on't 1(11l withhi tlhe m i l o aiil l OWli(1 lhi' IT(CO'E'lV, 1liiiil 'tVP vjillii's ll'. 14- S (ll, lll 0(.08diiilihgulrtlhuns/Euli lh'/I./tlnlneih ltl tIhe 95'frf hifii eln' e level. h'

13

I 4

'!i -. . . . . ...

'- 2/"• 't, "r - ,u

I , , ,,."

C. .... . ..... • ........ ..

5; E-t I .

- -. . . .. .4.

4 ,

*1.i

'I! .. -

- i t

411"

Micoojot-n oc l. of Ow spec it's P ostinodiu10 (oI ow( illfit!h [)IUOCI stinttarf Ion cl NoJavssa Isicirid Ftagc'l1c')tc la-,11 r iql culls I 0015sC.hi dlh

W . -'.I;--

I

. ~ ~ ~ ~ ~ ~ , . . ....

/k

I gur c3

Renl temtodasi, LUsj' tanitf~i tcew; rothscht hit front Na vcsso Island, West Indies,Asuckeor (arrow) is clearly identified, 1-1 & E X 100,

e.4tFigure 4

Cestodcl bladder worm found bet ween thIe ri qltt unrd left I obes of the li ve.r,Freuqtr manati ficents rathsc hiId i .H & f: X 40.

16

oioe hor I MoN to um orxift um on Nov os Isiud V es Indis

Cloeu V \'IO of ilw folioqv of Mopil oxife urn

. . .... . ... .. . .... .. ... .. ..

Figure 7

C01OrrCrt dormcr IIIH itkCOUUso by 111C $sop Of tMCtOp urnI taXi fe lIIur,Navassa I sland

Ar tiljr', (rrnuicniSi s, o Isk vi olin,; bIjt of [NsrvuJS5u(1 l, 'I, Wes~t I rsiess

Hicjure 9

Cal) cell hyperplasi a (arrlow), thicaken;.1g , menidncies , gaoofH & I, X 450.

Figure 1

5 poligoi ask gray matter, brain, goal.H- & E X 40

19

Vod u*, e nero (arw, bri, goa

vt I !,A

*~ ~ ¾" XF 20.0

. ..- -. ", .' .

-5 '~ , 4 " ' C" -W I • • • ' • , •2 t,, ' ,' ,A. '', . --. ,-': • '! • •" ' -'&; • t • ; .

* "s , . ,, ±. , o . • • " ' , • , :• " . .t• e , . . ., ". . • , • ' ,'•"w? " " *¼

• ,'r .' ~ .%•,.. , •,

* r '. ..

',',. •, .;• •1 • '; Fi gur 11," ' " ; "' .

V acualut' c .. d * neu a.-"n .(ar ow ,. a , , -t' "''• '• t•,•. . " .. S EX'. ',., 200: . .,, • ,,, ', '"> ." ,,

rF:•, .-- ,l, ' ... .( ., . . , 4 \

" .w ' ' ", ' . ' I , , ' , ' i • • ' - " 1 ! " . L ,

•. . , '"• b ,, ' , . . ." " "" "' • ' o Ž . A

',, Figuj 12 •

1II & E- X 200,

!'20

, ,

Figuie 13

Rectangular neuronal cytoplasmiic inclusion, goatH & E X 325,

Figure 14

P'ulmonary granuloma, lung, goot.H & E X 200.

21

- f4

its?

Sevra sU1opo di"cssmseerms, ro4 ,

I tp A

4X 01,

Fi;gure 16

High nigni Sevation sars o sporidia I cysts, ma sseter munscI e, rat.Nt h asneo

H & E X 450.,

224

/ b-I

, £ . • •,,r : ,,•¸1 %• • - ,

r rI'Figure 17

Sarcospo kiloa! cyst i longitudinal section, rnasseter musc I0n, ratH & E X 450,

.,.Ofa

'11v

Adul •oi yl n m ., , o , ep th li m rut ,•

SS .

• .... . ,,,, , p);,'du,'. fro,

Figur 18ia~ecoyAdult Gongylonemo (arrow), epithaeliu, rut2

7.....--&E X 450.

bes2 •vailable copy.23

Figure 19

F iqcuie 20

Sulp~hur I(JOUIVUI, ill C) pool of p)jylolyopliui,:UCjClc IU-,Lkocyt(5,bot ryamycosks, roit

1.1 & E~ X 1000,

24

r4ý " ,se

Figure 21

Sul phut gid nul e (a~rrow) compri sed of ' rarmr positive Iu. teria,purulent exudaite, Inandible, rot.

Fi & E X 450,

%~M O N(

Ak v 14

F ig u re 22

Shnplc or collicdal g oiter, felIine . Note thle large d ited foil iclItsH & E X 40.

2b

u~r:~~.4;r 'v& AzIre , -.

too , .'.

"II

Fijui 23

Grariulor dstous nephritis, kidney, felineHi & c X 100,

?I ,,

if 4404'

~ ~~':;y'ALI. A~

ilil

Figjo e 24

Graulorrotous glossitis, tonqe felirHI & E X 100,

[:Rprociuc ej -fro mn

26

REFERENCES

1. Anon., Syllabus of the microslide study set of the pathology of nonhuman primates,gongylonemiasis, Washington, D . C. 1968.

2. Anon., Poisonous and Injurious Plants of the U. S. Virgin Islands. USDA MP 882.United States Department of Agriculture.

3. Baker, H. J , and Lindsey, J . R., Equine goiter due to excess dietary iodide.J. Am. Vet. Med. Assoc. 153:1618-1630/ 1968.

4. Biester, H. E ., and Schwarte, L. H., Diseases of Poultry, Ames, Iowa: The IowaState University Press, 1965.

5. Brown, R. J., Baker, R. 0., Home, A. F., Kupper, J. L., and Davis, R. D.,Plasmodium infection in the man-of-war bird in Navassa Island, West Indies.J. Fla. Vet. Med. Assoc. June 1972, p. 8 1.

6. Brown, R. J., Conran, P. C., and Garner, F. M., Cap cell hyperplasia in thewildebeest, Am. J. Vet. Res., 31:547-549, 1970.

7. Craig, C. F,, and Faust, E. C., Clinical Parasitology, Fifth ed, Lea and Febiger,Philadelphia, Pa., 1953.

8, Dunaia, R,, Navassa 1928. QST, 53:59-61, December 1969. I9. Earle, K., Personal communication, Armed Forces Institute of Pathology, Washington,

D. C., 1968.

10. Foilis, R. H., Defic'.,ncy Diseases, Springfield, IIl .: Charles C Thomas, 1958.

11. G 1dusek, D . C., (Ed.), Slow, latent and temporate virus infections. Bethesda,Md.: U. S. Public Health Service, 1965.

12. Kilkuth, W., Immunbiologische und Chemotherapeutische Studien an verschiedenenStammer von Vogelmalarie. Zentra Lbl . P. Bakt. I . Orig. 121:401, 1931 .

13. Levine, N. D ., and Hanson, H. C . Blood parasites of the Canada goose. J.Wildlife Mgt., 17:185, 1953.

14. Levine, N D., Proto;zoan Parasites of Domestic Animals and Man, Urbana, III,Univ. of III. Press, 1960.

15. Morton, J . F., Wi Id Plants for Survival in South Florida. Miami: HurricaneHouse, 1962.

16. Pattison, I. H., Gordon, W. S., and Millison, G. C., Experimental Productionof Scrapie in Goats. J. Comp. Path., 69:300-312, 1959.

17. Proctor, G. R., Observations on Navassa Island, Geonotes, Vol. II . The Instituteof Jamaica, 1959.

18. Schocet, S. S., Lampent, P. W., and Earle, K. M., Neuronal changes inducedby intrathecal vincristine sulphate. J . Neuropath. and Exper. Neurol27:645-659, 1968.

19. Smith, H., and Jones, T. C., Veterinary Pathology. Third Ed, Philadelphia,Pa : Lea and Febiger, 1966,

20. Soulsby, E . J . L., Helminths, Arthropods and Protozoa of Domestic Animals,Baltirnore, Md., " nW- o.,T9&8.

21. Soulsby, E . J . L, Textbook of Veterinary Medical Clinical Parasitology,Vol.., , Pa..: I-A-vPhTi.

28