Medical Microbiology

11 – 13 daysarereportedforS.hominisandS.suihominis,respectively.Ex-

aminationoflargepopulationgroupsinGermany(n=approx. 150 0)and

France(n= 350 0)revealed 1 .6%and 2 %Sarcocystisexcreters,respectively.

Clinicalmanifestations,diagnosis,therapy,andprevention.Bothspecies

cancauseshort-lived(sixto 48 hours)symptomswithin 24 hoursofeating

meatcontainingcysts,forexamplenausea,vomiting,anddiarrheaaswellas

amildfever.S.suihominisismorepathogenicthanS.hominis.

AnintestinalinfectionwithSarcocystiscanbediagnosedbydetection

ofsporocysts(1 4! 9 lm),ormorerarelyoocysts(approx. 20! 13 lm)

(Fig.9. 11 k,p. 50 4)instoolusingtheSAFCortheflotationmethod(p. 62 1).

ThetwoSarcocystisspeciescannotbedifferentiated.Aneffectivetherapyhas

notyetbeendeveloped.Preventionconsistsinboilingordeep-freezing

(–20 8 Cforthreedays)ofporkandbeef.

Cryptosporidium

Causativeagentofcryptosporidiosis

&CryptosporidiosisinhumansispredominantlycausedbyCryptosporidium

hominis(=humangenotypeofC.parvum)andthebovinegenotypeofC.par-

vum.Humansareinfectedbyperoralingestionofinfectiveoocysts.Inimmu-

nocompetentpersons,theinfectionremainsinapparentormanifestsasa

self-limitingdiarrhea.Persistent,choleralike,life-threateningdiarrheasare

observedinAIDSpatients. &

Parasitespeciesandoccurrence.Atleast 10 speciesofthegenusCryptospor-

idiumandseveralgenotypesarecurrentlyknownthatoccurmainlyaspara-

sitesoftheintestine(andrarelyofotherorgans)inhumansandnumerous

speciesofmammaliananimals,birds,andreptiles.Cryptosporidiumhominis

isaparasiteofhumansandmonkeys,thebovinegenotypeofC.parvumin-

fectsmanyspeciesofmammaliananimals(ruminants,dogs,cats,rabbits,ro-

dents,etc.)andhumans.Otherspeciesoriginatingfromanimalshavebeen

foundoccasionallyinAIDSpatients,includingCryptosporidiumcanis(host:

dog)Cryptosporidiumfelis(host:cat),CryptosporidiummeleagridisandCryp-

tosporidiumbaileyi(hosts:birds).

Cryptosporidiosisoccursworldwide.Themeanprevalencesinhumans

differindevelopedanddevelopingcountriesandareabout 2 %and 6 %re-

spectivelyforimmunocompetentpersonswithdiarrheaand 14 %and 24 %

respectivelyinHIV-positivepatients.Prevalencesexceeding 50 %arealso

knowninthelattergroup.Amongdomesticatedanimals,particularlyhigh

prevalencesareobservedamongyoungcalves(often 20 – 100 %).

Cryptosporidium 517

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Kayser, Medical Microbiology © 2005 Thieme