Medical Microbiology

Platyhelmintha(syn.Platyhelminthes) 571

encapsulatedorcalcifiedcystsarepresent.Symptomsmayappearafter

monthsoryearswhenoneormorecystsbegintodisruptorganfunctions

duetotheirsize,expansivegrowth,orlocalization(Table 1 0. 3 ).Acutesymp-

tomsmayappearfollowingspontaneous,traumatic,orintraoperativecyst

ruptures,wherebythereleaseofantigencontaininghydatidfluidcancause

symptomsofanaphylacticshock.Thereisalsoariskthatprotoscoleceswillbe

releasedanddevelopintonewcystsinthehumanhost(secondaryCE).On

theotherhand,cystrupturecanalsoresultinspontaneouscure.

Diagnosisisbasedondetectionofcystsusingimagingtechniques(ultraso-

nography,computertomography,thoracicradiography,etc.)inconnection

withserologicalantibodydetection(Table 11. 5 ,p.625).Specificantibodies

occurinabout 90 – 100 %ofpatientswithcystichepaticechinococcosis,but

inonlyabout 60 – 80 %ofcaseswithpulmonaryechinococcosis.Diagnostic

cystpunctureisgenerallynotadvisableduetotherisksdescribedabove(sec-

ondaryechinococcosis,anaphylacticreactions).

Therapy.ThediseasecanbecuredbyremovingtheEchinococcuscystssur-

gically.Inoperablepatients(e.g.,withmultiplecystsinlungsandliver)canbe

treatedduringseveralmonthswithalbendazoleormebendazole.Che-

motherapyresultsincureinabout 30 %ofcasesandinimprovementina

further 30 – 50 %(WHO, 1 996).PAIR(punctureaspirationinjectionreaspira-

tion)therapyisanewtechniquestillunderevaluation:afterpuncturing

thecysts(notallcystsaresuitable,e.g.,pulmonarycysts!)underultrasonic

guidance,mostofthehydatidfluidisaspirated,afterwhichanadequate

amountof 95 %ethanolisinjectedintothecyst,leftinitfor 15 minutes

andremoved(reaspirated).Ifeffective,thePAIRprocedureoftensucceeds

inkillingthegerminativelayerandprotoscolecesbyethanol.Sincelong-

termexperiencewiththismethodislacking,itisrecommendedthatthepro-

cedurebeaccompaniedbyashort-termdrugregimen(WHO, 1 996).

Controlandprevention.ControlofCEinhumansincludesregularmass

treatmentofdogstoeliminateE.granulosus,preventingaccessofdogstovis-

ceraofdomesticorwildanimals,anddogpopulationcontrol.Specialhygie-

nicprinciplesmustbeobservedwhenhandlingdogsinendemicareas.

Echinococcusmultilocularis(DwarfFoxTapeworm)

Causativeagentofalveolarechinococcosis(AE)

E.multilocularisiswidespreadinthenorthernhemispherewithendemic

regionsinEurope,Asia(Turkey,Iran,Russia,andborderingcountriesall

thewaytoJapan),andNorthAmerica(Alaska,Canada,northernandcentral

USstates)(Fig. 1 0. 11 ).InCentralEurope,theparasiteiswidelydistributed

withprevalencelevelsinfoxesexceeding 50 %insomeareas.

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Kayser, Medical Microbiology © 2005 Thieme