Medical Microbiology

574 10 Helminths

DespitethefrequentandwidespreadoccurrenceofE.multilocularisinfoxes,

theincidenceofAEinhumansiscurrentlylow.Statisticsonnationalorre-

gionalincidencesrecordedinrecentyearsinFrance,Germany,Austria,and

Switzerlandvariedbetween0.02and 1 .4newcasesper 100000 inhabitants

peryear.Itispossiblethatthegrowingfoxpopulationandincreasinginva-

sionofcitiesbyfoxes,combinedwithotherfactors,mayraiselevelsofinci-

denceinthefuture.InahighlyendemicfocusinChina 4 %ofseveralthousand

personshaddocumentedAE.

Pathogenesisandclinicalmanifestations.Theinitialphaseofaninfectionis

alwaysasymptomatic.Followingalongincubationperiod,usually 10 – 15

years,theinfectionofthelivermaypresentwithsymptomsresemblingthose

ofamalignanttumor(Table 1 0. 3 ).Theinfectionrunsaslowlyprogressing,

chroniccourse,lastingseveralweekstoseveralyears.Thelethalityrate

canexceed 94 %inuntreatedpatients.Spontaneouscureispossible,although

noreliablestatisticsareavailable.

Diagnosis.ThediagnosticprocedureforAEisthesameasforCE.Sensitive

andspecificmethodsareavailableforserologicalantibodydetection(ELISA,

Westernblot)(Table 11. 5 ,p.625).

Therapy.Radicalsurgicalremovaloftheparasitesispotentiallycurative,but

notalwaysafeasibleoption(inonly 20 – 40 %ofclinicallymanifestcases).Dur-

ingtotheinfiltrativemodeofgrowthofE.multilocularismetacestodesitis

impossibletobecertainthatallpartsoftheparasitehavebeenremoved,so

thatchemotherapywithmebendazoleoralbendazolemustbecarriedout

followingsuchsurgeryforatleasttwoyearswithpatientmonitoringcontin-

uedforupto 10 years.Chemotherapylastingyears,orevenforthelifeofthe

patient,isrequiredininoperablecases(WHO, 1 996).Long-termstudieshave

revealedthatchemotherapycombinedwithothermedicalmeasuressignifi-

cantlyincreaseslifeexpectancyandqualityoflifeinthemajorityofpatients.

Controlandprevention.Trialsarecurrentlyinprogresstoevaluatedrug-

basedcontrolofE.multilocularisinfoxpopulations,butanestablished

andeffectivecontrolprogramisnotyetavailable.Personalprophylaxisinen-

demicareasshouldincludespecialprecautionswhenhandlingpotentially

infectedfoxesandotherdefinitivehosts.Thoroughwashing,andbetter

yetcooking,oflow-growingcultivatedandwildplantsandwindfallfruitbe-

foreeatingthemandwashingthehandsafterworkingwithsoilarefurther

basicpreventivemeasures.Personsknowntohavehadcontactwithdefini-

tivehoststhatareconfirmedorpotentiallyinfectedcarriers,orwhoarein

frequentcontactwithfoxesorareexposedtootherconcreteinfectionrisks

canhavetheirbloodtestedforantibodiestoE.multilocularis,theobjective

beingexclusionorearlyrecognitionofaninfection.

10

Kayser, Medical Microbiology © 2005 Thieme