EnzymeimmunoassayforthequalitativedeterminationofIgGclassantibodiesagainstEchinococcusinhumanserumorplasma(citrate).Echinococciaremicroscopiccestodes(tapeworms)of1-6mmwhicharedependentontheirgenusfoundeitherindogsorothercanids(E.granulosus)orinfoxes,coyotesandwolves(E.multilocularis).Intheirlarvalstagetheyarethecausativeagentofhumanechinococcosis(Hydatiosis,orhydaticdisease).Theadulttapewormsresideinthesmallbowelofthedefinitivehosts,andgravidproglottidsreleaseeggsthatarepassedinthefeces.Afteringestionofasuitableintermediatehost,theegghatchesinthesmallbowelandreleasesanoncospherethatpenetratestheintestinalwallandthroughthecirculatorysystemintovariousorgans,especiallytheliverandlungs,whereitdevelopsintoacyst.Echinococcusinfectionsremainsilentforyearsbeforetheenlargingcystscausesymptomsintheaffectedorgans(liver,lung,andlesscommonlyotherorgansasbrain,bone,heart).E.granulosusoccurspracticallyworldwide,andmorefrequentlyinrural,grazingareaswheredogsingestorgansfrominfectedanimals.E.multilocularisoccursinthenorthernhemisphere,includingcentralEuropeandthenorthernpartsofEurope,Asia,andNorthAmerica.Althoughhumancasesarerare,infectioninhumanscausesparasitictumorstoformintheliver,thelungs,andlesscommonly,thebrain,andotherorgans.Ifleftuntreated,infectioncanbefatal.