High prevalence of large trematode eggs in schoolchildren in Cambodia
a b s t r a c t
Large trematodeeggs(LTE)resembling Fasciola spp. eggswerereportedlyfoundinthestoolsofschoolchil- dren inKandalprovince,Cambodia.ThisstudyaimedtoassesstheprevalenceofLTEinthestoolsof children attendingtheaffectedschool,identifypotentialriskfactorsforinfectionandascertainthe trematode species.Weperformedacross-sectionalstudyinvolvinganin-depthquestionnaireadmin- istered toschoolchildrenattheaffectedschool,andexaminedcattledroppingsinthesurroundingarea and theliversofslaughteredcattle.Threestoolsampleswereexaminedperchild,usingKato–Katzand formalin–ether concentrationtechniques.Inaddition,bloodserumenzyme-linkedimmunosorbentassay (ELISA) andcoprologicalpolymerasechainreaction(PCR)wasconductedforspeciesclarification.Cattle droppings wereexaminedbycupsedimentationandcoprologicalELISA.LTEwereobservedinthestools of 106schoolchildren(46.5%).Twobloodserumsamplesfromschoolchildrenwerepositivefor Fasciola hepatica in afirstELISAbutwerenegativeinaconfirmationimmunofluorescenceantibodytest.Outof221 PCR samples,onlyonetestedpositivefor Fasciola spp. andnonefor Fasciolopsis buski. Theconsumption of rawaquaticplants(oddsratio(OR)=3.3)andfermentedfishsauce(OR=2.1)weresignificantlyassoci- ated withLTEinthestool. Fasciola spp. flukeswereobservedin18.3%of191cattlelivers.Theprevalence of fascioliasisincattledroppingswas88.8%.Thelowprevalenceofschoolchildrenthattestedpositivefor Fasciola spp. withspecificmoleculardiagnosticsandwhohadnodiagnosticevidenceof F. buski strongly indicates thatthemajorityofmicroscopicallyobservedLTEarefrom Echinostoma spp. Fasciola spp. transmission fromcattletohumanispossibleandpublichealthservicesneedtobealertedaccordingly.