Investigation of Outbreak of hepatitis E with bimodal peak in rural area of Bhavnagar in 2010

7/31/2019 Investigation of Outbreak of hepatitis E with bimodal peak in rural area of Bhavnagar in 2010

1/5

190 Annals of Tropical Medicine and Public Health | May-Jun 2012 | Vol 5 | Issue 3190

ORIGINAL

ARTICLE

Access this article online

Quick Response Code: Website:www.atmph.org

DOI:10.4103/1755-6783.98615

Outbreak of hepatitis E with bimodal peak in rural area of Bhavnagar,

India, 2010

Devang A. R aval, Naresh T. Chauhan, Rajesh S. Katara1, Pankhuri P. Mishra2, Dharmendra V. Zankar

Departments of Community Medicine, 1Microbiology, Government Medical College, Bhavnagar, 2Epidemiologist, Integrated DiseaseSurveillance Project,Bhavnagar, Gujarat, India

ABSTRACT

Context: Rise in the number of jaundice cases were reported on 24th of June 2010, in Dhola village, India.

We investigated the outbreak to identify the source of infection and to facilitate control measures. Materials

and Methods: We conirmed the outbreak by reviewing the rate of acute viral hepatitis in the year 2009-10.

We deined a case of acute hepatitis as an acute illness with (a) discrete onset of symptoms and (b) jaundice

or elevated serum aminotransferase levels, since March 2010 in Dhola village. We described the outbreak in

terms of time, place, and person. We tested 20 blood samples of the case patient for hepatitis B surface antigen

(HBs Ag), and immunoglobulin M (IgM) antibody for hepatitis A and E. We collected water samples for the

bacteriological examination, and to test free chlorine in the water. Results: A total of 137 cases (attack rate

27.2/1000) were reported in this outbreak from March to August 2010. The attack rate was highest among the

age group of 2029 years. The attack rate was signiicantly higher in male (35/1000) than in female (18/1000).

Out of 20 case-patients, 19 were found positive for hepatitis E virus (HEV) IgM antibodies. The water samples

taken from households contained more than 10 coliforms in 100 ml sample. The relative risk of developing

hepatitis E among people using pipeline water against those using ground water was 3.23 (95% CI of RR 1.59,

6.57). Conclusion: Outbreak that affected Dhola village was due to hepatitis E virus. Fecal contamination of

water was the most likely source of this bimodal outbreak of hepatitis E.

Key words: Bimodal outbreak, cohort study, hepatitis E, India

Correspondence:

Dr. Naresh T. Chauhan, Shivganga Flats, Opp. Bavlia Hanuman Temple, Bhayanini Wadi, Bhavnagar, Gujarat-364003, India.

E-mail: [email protected]

Introduction

HepatitisE,formerlyknownasenterically-transmitted

non-A,non-Bhepatitis,isanacute,icteric,self-limiteddiseasewidelyspreadinAsia,Africa,MiddleEast,and

CentralAmerica.[1-6]Viralhepatitiscontinuestobea

majorpublic healthproblem inIndia.[7,8]Evidenceof

hepatitisEvirus(HEV)wasfirstreportedin1980,in

India.[9]The fecal-oral route is the primary mode of

transmissionofHEV[1]anditisassociatedwithboth

sporadic infections and epidemics inareaswithpoor

sanitationandweakpublic-healthinfrastructures. [4]

HEVisasmallRNAviruswhichbelongstothegenus,Hepevirus, of the family, Hepeviridae.[6] Hepatitis Einfectionsoccurlessfrequentlyindevelopedcountries,and only occur in those individuals who had beeninfectedwhiletravelinginanareawhere thevirus isendemic.[1]However,autochthonous(locallyacquired)occurrences of hepatitis E cases were also reportedin developed countries, recently.[3,10-12] The virus alsospreadsthroughperson-to-person,butsuchaspreadislesscommon,andasecondaryattackraterangesfrom0.7%to2.2%amongsusceptiblehouseholdcontactsofpatient.[13]Theincubationperiodrangesfrom2weeksto2months,usually1monthto45days. [7]Pregnantwomen affected by acute viral hepatitis E are morelikelytodevelopacuteliverfailure(ALF);however,thefatal outcomemayremain same as innon-pregnant

womenandmenwithALF.[14]Thetreatmentremainssymptomatic.The identificationof specific sourceofinfectionisofmajorimportancetocontroltheoutbreak,asthestandardcontrolmeasureslikechlorinationofwatermaynotbeeffective.[15]

Riseinthenumberofjaundicecaseswerereportedon


2/5

191Annals of Tropical Medicine and Public Health | May-Jun 2012 | Vol 5 | Issue 3

24th of June 2010, in Dhola Junction village, whichis located 50 km from Bhavnagar city, and havingpopulationof5045.Rapidresponseteaminvestigatedtheoutbreaktoidentifythesourceofinfection,andtofacilitatepossiblecontrolmeasures.

Materials and Methods

Descriptive epidemiology

We reviewed Integrated Disease Surveillance Project(IDSP)weeklyreporting data onacuteviralhepatitisfor the year, 2009-10, to confirm the outbreak.Wedefined a caseof acute hepatitis as an acute illnesswith (a) discrete onset of symptoms and (b) jaundiceorelevatedserumaminotransferaselevels,sinceMarch2010inDholavillage.Datawerecollectedthrough(1)adoor-to-doorsurveyand(2)reportingunderIDSP.Wealsocollectedinformationregardingthedateofonset,age,sex,placeofresidence,treatment,andlaboratory

investigation.We calculated theattackratesof acutehepatitis by age and sex. We analyzed time, place,and persondistribution of cases.We constructed anepidemiccurvetostudythedynamicsoftheepidemic.Wedividedthevillageintosixareasbytheirlocation(AtoF).Wepreparedanincidencemaptostudythedistributionofcases,andtoformulatehypothesis.WeusedEpiInfo3.5.1toanalyzeourdata.

Environmental investigation

We interviewed case-patients to collect informationregardingwaterquality, thesourceof drinkingwater,drainagesystem,andimportanteventsbeforetheonsetofillness.Wealsocollectedinformationregardinganypublicgatherings,exposuretooutsidefood,andlocalfood vendors. We examined the underground tank,which collects and stores the water to supply to thevillage.We used orthotolidine test to detect residualchlorinefromwatersamplestakenatvarioushouses.

Laboratory methods

We collected blood samples of 20 case-patients forthedetectionofimmunoglobulinM(IgM)antibodiesagainst hepatitis A and E virus, and for hepatitis Bsurfaceantigen(HBsAg),usingcommerciallyavailable

enzyme-linked immunosorbent assay (ELISA) kits(Adaltis, Italia, Italy).We collected samples ofwaterthat was supplied to the village through pipelinefrom Rajpipla. We further collected samples fromundergroundwater tankand fromindividualhouses.Thesewatersamplesweretestedtodetectthepresence

ofcoliformbacteriausingthemostprobablenumber(MPN)method.Weconsideredwaterasacceptable,ifitdidnotcontainmorethan10coliformsina100ml

sample.

Analytical epidemiology

Basedontheenvironmentalinvestigation,wegeneratedhypothesis that the presence of open drain, publictoilets, and septic tank close to leaking regulatoryvalves inthepipelinewerethemost likelysourcesofthis outbreak. We conducted a retrospective cohortstudytotestthehypothesisregardingthesourceofthis

outbreak.Weusedthesourcesofwatersupplytodividethevillageintotwocohorts,1)areasthatweresuppliedwaterthroughpipeline fromoverheadwater tankand2)groundwatersupply.Weestimatedrelativeriskwith95% confidence intervals (CI), and tested statisticalsignificancebyusingthechi-squaretest.

Results

Descriptive epidemiology

NocaseofviralhepatitiswasreportedfromVallabhipurblock, where Dhola village was located as per theIDSPdata2009-10.Atotalof137cases(attackrate27.2/1000)werereportedinthisoutbreakfromMarchtoAugust2010.Therewere95male and 42 femaleaffected.Thedisease affectedall theagegroups.Theattackratewashighestamongtheagegroupof2029yearsandlowestamongchildren


3/5


Laboratory results

A total of 20 sera from case-patients were tested;19 were found positive for HEV IgM antibodies.Bacteriologically,samplesofwaterthatcomethroughpipeline from Rajpipla and underground tankwere found satisfactory. Water samples taken fromhouseholdscontainedmorethan10coliformsina100

mlsample.

Environmental investigation

Dholavillage ishavingtwo sources ofwater supply;oneisthepipelinefromRajpipla,60kmawayfromthevillage,andsecond isgroundwater supply inrailwaycolony. Water that comes from Rajpipla is storedin the underground tank, and supplied, thereafter,through theoverheadtank.Chlorinationof water intheunderground tankis donebefore itispumpedinthe overhead tank. Water supply in the village wasintermittent,onceinthreetofourdays.Watersampletestedfromtheundergroundtankhadresidualchlorine

more than 1ppm (parts permillion).Water samplestested for residual chlorine levels at different pointsin the villagewere found below 0.5 ppm. Commonlatrines of village, septic tank, and open drainwerelocated in close vicinity of the water supply system[Figure 2]. Pipelines supplying water were found tobecrossedbythedrainagepipeline,aslaterwaslaiddownsuperficially.Everytime,whenwaterispumped,leakages inregulatoryvalvesresults inwaterlodgingaroundthevalves.Intermittentwatersupplyleadstoanegativepressureinpipesduringperiodsofnoflow,permitting inward suction of contaminated water

lodgedaroundvalves[Figure3].Otherpossiblesourceswhichmightcausehepatitis outbreakhadbeenruledout.

Analytical epidemiology

Higher incidence rate (31.7/1000) was observedamongpeoplelivinginareahavingwatersupplyfromoverhead tank as compared to people living in areahaving ground water supply (9.5/1000).The relativeriskforthoseexposedagainstthosenon-exposedwas3.23(95%CIofRR1.59,6.57).Thedifferenceintheattackratewasalsofoundtobestatisticallysignificant(X2=11.9,P


4/5

193Annals of Tropical Medicine and Public Health | May-Jun 2012 | Vol 5 | Issue 3

Table 2: Incidence rates of acute hepatitis according to

suspected exposure in Dhola, Bhavnagar, India, 2010

Suspected

exposure

Number

of people

affected

Number of

people not

affected

RR 95% CI P- value

Tank water supply

(Area A to E, n=4 203)

129 4074 3.23 1.59-6.57


5/5


thismanuscript.WearealsothankfultoDr.MPSingh,Head

ofCommunityMedicineDepartment,GovernmentMedical

College,Bhavnagar,forhissupport.

Ethical approval

This studywas done asa part ofresponsetopublichealth emergency (outbreak); ethical approval not

obtained.

References

1. Balayan MS. Type E Hepatitis: State of the Art. Int J Infect Dis

1997;2:113-20.

2. Tandon BN, Gandhi BM, Joshi YK, Irshad M, Gupta H. Hepatitis

non-A, non-B: The cause of major public health problem in india. Bull

WHO 1985;63:931-4.

3. Dalton HR, Bendall R, Ijaz S, Banks M. Hepatitis E: An emerging

infection in developed countries. Lancet Infect Dis 2008;8:698-709.

4. Labrique AB, Thomas DL, Stoszek SK, Nelson KE. Hepatits E: An

emerging infectious disease. Epidemiol Rev 1999;21:162-79.

5. Arankalle VA, Chadha MS, Tsarev SA, Emerson SU, Risbud AR,

Banerjee K, et al. Seroepidemiology of water-borne hepatitis in India

and evidence for a third enterically-transmitted hepatitis agent. NatlAcad Sci 1994;32:3428-32.

6. Ahn JM, Kang SG, Lee DY, Shin SJ, Yoo HS. Identication of HEV

isolates and determination of the seroprevalence of HEV in Korea. J

Clin Microbiol 2005;43:3042-8.

7. Monthly Newsletter of National Institute of Communicable Diseases.

Outbreaks of viral hepatitis E: Public health system needs to be alert.

CD Alert, Delhi: National Institute of Communicable Disease; vol. 4,

2000. p. 1-8.

8. Acharya SK, Madan K, Dattagupta S, Panda SK. Viral hepatitis in

India. Nat Med J India 2006;19:203-7.

9. Khuroo MS. Study of an epidemic of non-A, non-B hepatitis: Possibility

of another human hepatitis virus distinct from post-transfusion non-A,

non-B type. Am J Med 1980;68:818-23.

10. Clemente-Casares P, Sonia P, Buti M, Jardi R, Martn M, Boll-Mas

S, et al. Hepatitis E virus epidemiology in industrialized countries.

Emerging Infect Dis 2003;9:448-54.

11. Meng XJ. Recent advances in hepatitis E virus. J Viral Hepat

2010;17:153-61.

12. Thomas DL, Yarbough PO, Vlahov D, Tsarev SA, Nelson KE, Saah

AJ, et al. Seroreactivity to hepatitis E virus in areas where the disease

is not endemic. J Clin Microbiol 1997;35:1244-7.

13. Aggarwal R. Hepatitis E: Historical, contemporary and future

perspactives. J Gastroentrol Hepatol 2011;26(Suppl 1):72-82.

14. Bhatia V, Singhal A, Panda SK, Acharya SK. A 20-year single-center

experience with acute liver failure during pregnancy: Is the prognosis

really worse? Hepatology 2008;48:1577-85.

15. World Health Organization. Guidelines for drinking water quality.

2nd ed. Addendum. Microbiological agents in drinking water, 2002.

Available from: http://www.who.int/water_sanitation_health/dwq/

microbioladd/en/index.html). [accessed on 2010 Nov 22].

16. Gurav YK, Kakade SV, Kakade RV, Kadam YR, Durgawale PM. A

study of hepatitis E outbreak in rural area of Western Maharshtra.

Indian J Commun Med 2007;32:182-4.17. Martolia HC, Hutin Y, Ramchandran V, Manickam P, Murhekar M,

Gupte M. An outbreak of hepatitis E tracked to a spring in the foothills

of the Himalayas, India, 2005. Indian J Gastroenterol 2009;28:99-101.

18. Bali S, Kar SS, Kumar S, Ratho RK, Dhiman RK, Kumar R. Hepatitis

E epidemic with bimodal peak in a town of north India. Indian J Public

Health 2008;52:189-93.

19. Sreenivasan MA, Banerjee K, Pandya PG, Kotak RR, Pandya PM,

Desai NJ, Epidemiological investigations of an outbreak of infectious

hepatitis in Ahmedabad city during 1975-76. Indian J Med Res

1978;67:197-206.

20. Sailaja B, Murhekar MV, Hutin YJ, Kuruva S, Murthy SP. Outbreak

of waterborne hepatitis E in Hyderabad, India, 2005. Epidemiol Infect

2009;137:234-40.

21. Banerji A, Sahni AK, Rajiva, Nagendra A, Saiprasad GS. Outbreak

of viral hepatitis E in a regimental training. Med J Armed Forces India

2005;61:326-9.22. Das P, Adhikary KK, Gupta PK. An Outbreak investigation of viral

hepatitis E in South Dumdum municipality of Kolkata. Indian J

Commun Med 2007;32:84-5.

23. Integrated Disease Surveillance Project. Annual Report 2008. Available

from: http://idsp.nic.in/idsp/nicd/IDSP_2WeekCourse_DSO_Sept08/

Resources_les/6DaysDSO-TOT/IDSP_Annual_Report_2008_Final.

pdf. [accessed on 2010 Nov 22].

24. Integrated Disease Surveillance Project. Resource. Weekly reporting

2009, 2010. Available from: http://idsp.nic.in. [accessed on 2010

Nov 22].

25. National Family Health Survey-2005-06. Chapter 2- Household

population and housing characteristics. India, vol. 1, 2007. p. 36.

Available from: http://www.nfhsindia.org/NFHS-3%20Data/VOL-1/

Chapter%2002.pdf. [accessed on 2010 Nov 22].

26. World Health Organization. Surveilllance of drinking water quality.

WHO Monograph series 63. Geneva: WHO; 1976.

Cite this article as: Raval DA, Chauhan NT, Katara RS, Mishra PP,

Zankar DV. Outbreak of hepatitis E with bimodal peak in rural area of

Bhavnagar, India, 2010. Ann Trop Med Public Health 2012;5:190-4.

Source of Support: Government of Gujarat, India, Conict ofInterest: None declared.

Raval, et al.: Hepatitis E outbreak in rural area of Bhavnagar, India

Investigation of Outbreak of hepatitis E with bimodal peak in rural area of Bhavnagar in 2010

Documents

Transcript of Investigation of Outbreak of hepatitis E with bimodal peak in rural area of Bhavnagar in 2010