Medical Microbiology

604 10 Helminths

Therapyandprevention.Chemotherapywithalbendazoleisonlyindicated

insymptomaticcases.ProphylacticmeasuresincludecontrolofToxocara

infectionsincatsanddogs,especiallyinyounganimals,andreductionor

preventionofenvironmentalcontaminationwithfecesofdogs,cats,and

foxesespeciallyonchildren’splaygrounds.

Anisakis

Causativeagentofanisakiosis

Anisakisandrelatedroundwormgenera(Phocanema[=Pseudoterranova],Contrac-

ecum),liveintheintestinesofmarinemammalsorbirds.Thelarvaeofthesepara-

sites,whichareingestedbyhumanswithrawseafish,areknownasthecausative

agentsofeosinophilicgranulomasinthegastrointestinaltract(“herringworm

disease”).Inrecentyears,mostcasesreportedhaveoccurredinJapan.Reliable

prophylacticpracticesincludeheatingordeep-freezingoffish(–20 8 Cforatleast

12 – 24 hours).

Angiostrongylus

Causativeagentangiostrongylosis

Angiostrongyluscantonensis(syn.Parastrongyluscantonensis)occursinthesouthern

AsianandPacificarea,whereitinhabitsthelungsofrats.Thisparasitehasbeen

identifiedasthecauseofaneosinophilicmeningoencephalitisinhumans.Larval

stagesoftheparasitehavebeenfoundinthebrain,spinalcord,andeyesofpersons

whohadpreviouslyfallenill.Infectionresultsfromingestionofrawintermediate

hosts(snails)andtransporthosts(crustaceans)containinginfectivelarvaeofA.can-

tonensis.

Angiostrongyluscostaricensis(syn.Parastrongyluscostaricensis)occursintheUSA,

CentralandSouthAmerica,andAfrica,whereitparasitizesinthemesentericvessels

ofcottonratsandothervertebrates.Humaninfectionsarecausedbyaccidental

ingestionofintermediatehosts(snails)containinglarvae,resultingintheinvasion

ofmesentericvesselsbyparasitesanddevelopmentofinflammatoryintestinalwall

granulomas.Larvaearenotshedinstoolbecause,althoughtheparasitesproduce

eggs,nolarvaehatchoutofthem.

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Kayser, Medical Microbiology © 2005 Thieme