Current status of schistosomiasis and soil-transmitted helminthiasis in Beyla and Macenta Prefectures, Forest Guinea

TransactionsoftheRoyalSocietyofTropicalMedicineandHygiene105 (2011) 672–674

ContentslistsavailableatScienceDirect

Transactions

of

the

Royal

Society

of

Tropical

Medicine

and

Hygiene

jo u rn al h om epa g e : h t tp :/ / w w w . e l s e v i e r . c o m / l o c a t e / t r s t m h

Short

Communication

Current

status

of

schistosomiasis

and

soil-transmitted

helminthiasis

in

Beyla

and

Macenta

Prefectures,

Forest

Guinea

Mary

Hodges

_,

_Manso

_M.

_Koroma

_,

_Mamadou

_S.

_Baldé

_,

_Hamid

_Turay

_,

Ibrahim

Fofanah

_,

_Mark

_J.

_Divall

_,

_Mirko

_S.

_Winkler

_,

_Yaobi

_Zhang

a_{HelenKellerInternational,P.O.Box369,Freetown,SierraLeone} b_{NorthernPolytechnic,Makeni,SierraLeone}

c_{ProgrammeNationaldeLuttecontrel’OnchocercoseetlaCécité,RépubliquedeGuinée} d_{NewFieldsSouthAfricaLLC,29ChathamRoad,Irene,SouthAfrica}

e_{DepartmentofEpidemiologyandPublicHealth,SwissTropicalandPublicHealthInstitute,P.O.Box,CH-4002Basel,Switzerland} f_{UniversityofBasel,P.O.Box,CH-4003Basel,Switzerland}

g_{HelenKellerInternational,RegionalOfficeforAfrica,Dakar,Senegal}

a

r

t

i

c

l

e

i

n

f

o

Received23July2010

Receivedinrevisedform15July2011 Accepted15July2011

Available online 25 August 2011 Keywords:

Schistosomiasis

Soil-transmittedhelminthiasis Guinea

a

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Across-sectionalsurveywasundertakeninchildrenaged9–14yearsinBeylaandMacenta Prefectures,ForestGuinea.StoolsampleswereexaminedbyKato–Katzandurinesamples wereexaminedbythecentrifugationmethod.Theoverallprevalenceandintensityof infec-tionwas66.2%and462.4eggspergramoffaeces(epg)forSchistosomamansoni,21.0%and 17.8eggsper10mlofurineforS.haematobium,51.2%and507.5epgforhookworm,8.1%and 89.1epgforAscarislumbricoidesand2.4%and16.7epgforTrichuristrichiura.Theoverall prevalenceofschistosomiasis(S.mansoniand/orS.haematobium)was70.7%.The preva-lenceofschistosomiasiswassimilartothosereportedinthe1990sintheregion;however, theprevalenceofsoil-transmittedhelminthshassincefallen.Thesefindingsillustratethe needforschistosomiasiscontrolinGuinea.

© 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

1. Introduction

Schistosomiasis and soil-transmitted helminthiasis (STH), two of the most important neglected tropical diseases (NTD),areof publichealthsignificance in sub-Saharan Africa.1 _{Guinea has long been known to be} prevalent with these diseases.2,3 _{Surveys in the 1990s} showedthatinNZérékoréregion,ForestGuinea,the preva-lenceofSchistosomamansonirangedfrom1.5%to86.1%, that of S. haematobium from 14.0% to 75%, hookworm 20–80%, Ascaris lumbricoides 21.6–55.0% and Trichuris trichiura 3.2–19% according to the published data4,5 _as wellasdatafromtheMinistryofHealth(M.Bah,personal communication). A school health programme including

∗ Correspondingauthor.

E-mailaddress:mhodges@hki.org(M.Hodges).

dewormingsupportedbytheWorldBankstartedin1995 following thesurveys6 _{but by2008 <10%of school-age} childrenhadbeentreated,whilstnationalcoverageof de-worming in preschool-age children had been achieved, withregularcoverageof>90%since.7 _{Anationalcontrol} programmeforschistosomiasisdoesnotcurrentlyexist.

Thispaperpresentstheresultsofa recentsurveyon schistosomiasisandSTHconductedin2010inBeylaand MacentaPrefectures,NZérékoréregion,ForestGuinea,as partofthehealthimpactassessmentinpotentiallyaffected communitiesforaproposedcoalminingdevelopment.

2. Materialsandmethods

Across-sectionalsurveywasconductedin14villages. Ineachvillage,30schoolchildrenaged9–14yearswere randomlyselectedfromtheprimaryschoolsorfromthe 0035-9203/$–seefrontmatter © 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

M.Hodgesetal./TransactionsoftheRoyalSocietyofTropicalMedicineandHygiene105 (2011) 672–674 673 communitiesifnoschoolexistedinthevillage,balancing

forgenderratiowherepossible.Intotal,420school chil-drenwereselected,comprising262boysand158girlswith nomeanagedifference.

Informedconsentwasobtainedfromcommunity lead-ers and head teachers. The study included only those children who agreedtoparticipate. A singlefreshstool sampleandamid-day, post-exerciseurinesample were collectedfromeachchildwhowasthengivenasingledose ofalbendazole(400mg).Sampleswerebroughtbackand examinedonthesamedayinthelaboratory.Stool sam-plespreservedin10%formalinwereexaminedusingthe Kato–Katzthicksmearmethod.Oneslideperstoolsample waspreparedandwasexaminedforS.mansoniandSTH eggs.Parasiticinfectionwasrecordedandtheintensityof infectionwascalculatedandexpressedasnumberofeggs pergramoffaeces(epg).Forurinesamples,thevolumeof urinesampleswasmeasuredandurine containerswere centrifugedfor5min.Thesediment of urinewas trans-ferredontoaslideandwascoveredwithacoverslip.These wereexaminedunderalightmicroscopeandthenumberof S.haematobiumeggswasrecordedandintensityof infec-tionwasexpressedasnumberofeggsper10mlofurine (e/10ml).

Data were analysed using SPSS software v.18 (SPSS Inc., Chicago, IL, USA). A frequency table with 95% CIs wasprepared.Arithmeticmeanintensityofinfectionwas usedintheanalysis.8,9_{Degreeofintensityofinfectionfor} individualparasites wascategorised according toWHO recommendations.10_{Differenceswereanalysedusing} one-wayANOVAformeanage,Kruskal–Wallistestforintensity ofinfectionandPearson␹2_{testforprevalence.}

3. Results

AssummarisedinTable1,themostcommonparasites wereS.mansoniandhookworm.Theoverallprevalenceof individualinfectionswas66.2%(range 13.3–90.0%in14 sites)forS.mansoni,21.0%(range0–76.7%)forS. haemato-bium,51.2%(range6.7–93.3%)forhookworm,8.1%(range 0–33.3%)forA.lumbricoidesand2.4%(range0–6.7%)forT. trichiura.Therewerenosignificantdifferencesinany indi-vidualparasiticinfectionbetweenboysandgirls(P>0.05). Schistosomamansoniposedtheheaviestinfectioninthe area.Themeanintensityofinfectionwas462.4epg,with 33.3%ofchildrenheavilyinfectedand 24.0%moderately infected.ThesecondheaviestinfectionwasS.haematobium (17.8e/10ml),with8.8%ofchildrenheavilyinfected.The meanintensityofhookworminfectionwas507.5epg, how-evertheproportionofheavyinfectionswasrelativelylow (1.7%).InfectionswithA.lumbricoidesorT.trichiurawere bothlight,withnoheavilyinfectedindividuals.

Overall,86.7%(95%CI83.1–89.6%)ofthechildren sur-veyedhad atleastoneparasiticinfection:39.0%(95%CI 34.4–43.7%)were infectedwithone species,34.0% (95% CI29.5–38.6%)withtwospecies,12.6%(95%CI9.4–15.8%) withthree species and 1.0% (95%CI 0–1.9%) with four species.Theoverallprevalenceofschistosomiasis(S. man-soniand/orS.haematobium)was70.7%(95%CI66.2–74.9%), and16.4%(95%CI13.2–20.3%)ofchildrenwereinfected

withbothS.mansoniandS.haematobium. Table

1 Observed prevalence and intensity of infections (95% CI) in children aged 9–14 years in Beyla and Macenta Prefectures, Forest Guinea No. of subjects Schistosoma mansoni Schistosoma haematobium Hookworm Ascaris lumbricoides Trichuris trichiura Prevalence (%) Overall prevalence 420 66.2 (61.5–70.6) 21.0 (17.3–25.1) 51.2 (46.4–55.9) 8.1 (5.9–11.1) 2.4 (1.3–4.3) Sex Boys 262 65.6 (59.7–71.1) 23.7 (18.9–29.2) 53.8 (47.8–60.0) 7.3 (4.7–11.1) 3.1 (1.6–5.9) Girls 158 67.1 (59.4–73.9) 16.5 (11.5–23.0) 46.8 (39.2–54.6) 9.5 (5.8–15.1) 1.3 (0.4–4.5) Intensity of infection (epg or e/10 ml a) Overall mean epg 420 462.4 (389.9–534.8) 17.8 (11.6–24.0) 507.5 (398.9–616.0) 89.1 (12.9–165.3) 16.7 (0–38.0) 0 epg (%) – 33.8 (29.5–38.5) 79.0 (74.9–82.7) 48.8 (44.1–53.6) 91.9 (88.9–94.2) 97.6 (95.7–98.7) Low epg (%) b – 8.8 (6.5–11.9) 12.1 (9.4–15.6) 45.7 (41.0–50.5) 7.6 (5.5–10.6) 2.1 (1.1–4.0) Moderate epg (%) b – 24.0 (20.2–28.4) – 3.8 (2.4–6.1) 0.5 (0.1–1.7) 0.2 (0.0–1.3) Heavy epg (%) b – 33.3 (29.0–38.0) 8.8 (6.5–11.9) 1.7 (0.8–3.4) 0 (0.0–0.9) 0 (0.0–0.9) Sex Boys 262 481.0 (386.9–575.1) 21.7 (12.4–30.9) 616.0 (451.9–780.1) 105.6 (0–225.2) 24.2 (0–58.2) Girls 158 431.4 (317.3–545.5) 11.4 (5.4–17.4) 327.5 (235.6–419.4) 61.7 (18.6–104.8) 4.4 (0–10.7) aEggs per gram of faeces (epg) for all parasites, except S. haematobium that was measured in eggs per 10 ml of urine (e/10 ml). bIntensity of infection for each parasite infection was categorised according to WHO recommendations. 10

674 M.Hodgesetal./TransactionsoftheRoyalSocietyofTropicalMedicineandHygiene105 (2011) 672–674

4. Discussion

Theoverallprevalenceofschistosomiasisinthisstudy washigh,similartotheresultsfromsurveysinthe1990s.4,5 Thismaynotbesurprisingasnolarge-scalepraziquantel distributionhasbeenconductedinthisregion.Theactual distributionofS.mansoniandS.haematobiumvaried geo-graphically,illustratingtheirfocalnature.Mixedinfections ofbothS.mansoniandS.haematobium(16.4%)wereinline withpreviousreportsinothercountries.11,12_Thehighlevel of infectionreflectsthelocaltransmissiondynamics for schistosomiasis,aswatercontactisfrequentasthelocal streamsarethemainwatersourcesfordomesticuse,where childrenalsobathandplay.

Incomparison,theoveralllevelofSTHinfectionshas fallensincethe1990sinForestGuinea.Thisdeclinemay beattributedtotheannualcommunity-directedtreatment withivermectininthesecommunitiesforonchocerciasis control in individuals over the ageof 5 years that was introducedin1997andalsotothebiannualdeworming of children undertheageof 5years withmebendazole togetherwithvitaminAsupplementationthatstartedin 2006.ComparedwiththelowlevelofA.lumbricoidesorT. trichiurainfections,hookwormprevalenceremained rela-tivelyhigh,buttheintensityofinfectionwaslowwithonly 1.7%ofchildren withheavyinfections.Thismaybedue tothedrugsbeingused,asivermectinandmebendazole havelesseffectoverhookworms.13,14_{Asimilarsituation} wasalsofoundrecentlyintheneighbouringcountrySierra Leone.15

Thepresentsurveyisatimelyadditiontoour under-standingof thecurrentsituation ofschistosomiasis and STHinForestGuineaandillustratestheneedtocontinue and expand the national NTD control programme to includeschistosomiasiscontrol.Plansareunderwayforan integratedNTDcontrolprogrammetocommencein2011 inGuinea.

Authors’ contributions: MH conceived the survey and

designed thestudy protocol; MJD and MSW supported thestudydesign andmanagedthefield work;HT,MSB and MMK performed collection and interpretation of the data; IF performed collection, entry and interpre-tation of thedata; YZ performedthe final analysis and interpretation of the data; YZ and MH drafted and revised the manuscript. All authors critically reviewed and approved the final manuscript. MHis guarantor of thepaper.

Acknowledgements: Theauthorswouldliketoexpress

theirprofoundsadnessforthelossofAliouBah,a won-derful man withanamazingdisposition and dedication whopassedawayduringthefieldworkofthissurvey.The authorswouldalsoliketothankRioTintoforhelpwith

logisticsinthefieldandtheirsupportfollowingthedeath ofourdearcolleagueAliou.

Funding: ThesurveywasfundedbyRioTinto,SIMFERSA

(ImmeubleKankan,Citéchemindefer,BP848–Conakry, République de Guinée). The paper does not reflect the viewofthefunders.

Conflictsofinterest: Nonedeclared.

Ethical approval: Ethical approval for this study was

obtainedfromtheNational Ethics CommitteeofHealth Research,MinistryofPublicHealth,Guinea.

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