Medical Microbiology

556 10 Helminths

Clinicalmanifestations.Theinfectionmayrunaninapparentcourseor,

afteranincubationperiodoffourtosixweeks,becomesymptomaticwith

abdominalpain,hepatomegaly,fever,leukocytosisandeosinophilia(acute

phase),orhepatocholangiticsymptoms(chronicphase)andanemia.Occa-

sionally,theparasitesalsomigrateintootherorgansthantheliver.

Diagnosis.Themanifestationstobeexpectedduringthemigrationphaseof

theliverflukeincludemainlyleukocytosis,eosinophilia,andariseinliver-

specificserumenzymes.Detectionofeggs(Fig. 1 0. 1 ,p.543)instoolorduo-

denalfluidisnotpossibleuntilatleasttwotothreemonthsp.i.Inpatients

fromAsia,differentialdiagnosisoftheeggsofthesmallintestinalparasites

EchinostomaandFasciolopsis(Fig. 1 0. 1 ),whichareverysimilartothoseof

Fasciola,mustbekeptinmind.Otherdiagnostictoolsincludedetectionof

serumantibodies(Table 11. 5 ,p.625)andofcoproantigeninstool.

Therapyandprevention.Thedrugofchoiceistriclabendazole,originallyde-

velopedasaveterinarydrug,isnowregisteredadusumhumanuminseveral

countriesandisrecommendedbytheWHO.Theinfectioncanbeavoidedby

noteatingrawwatercressandotherplantsthatmaybecontaminatedwith

metacercariae.

LiverFlukes

10

m

m

a

5 mm

b

5 mm

c

Fig. 1 0.6 aFasciolahepatica,adultstagewithblood-filledintestinalbranches;

bDicrocoeliumdendriticum,adultstage;cOpisthorchisfelineus,adultstage

(Fig.a:K.Wolff,Zurich;c:V.Kumar,Antwerp).

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Kayser, Medical Microbiology © 2005 Thieme