Medical Microbiology

infection.Ofparticularimportanceinpreventionofprenataltoxoplasmosis

isprophylacticserologicalmonitoring,withonecheckpertrimesterasis

obligatoryin,forexample,Austria(Aspo ̈ck, 2000 p. 6 60).

Isospora

Causativeagentofisosporosis

ThecausativeagentofhumanisosporiosisisIsosporabelli.Afterperoralingestionof

sporulatedoocystsandreleaseofsporozoites,furtherdevelopment(schizogony,

gamogony)takesplaceintheepitheliumoftheuppersmallintestine,leadingfinally

tooocystformation.InAIDSpatients,encystedsporozoiteshavebeenfoundinvar-

iousextraintestinalorgans(lymphnodes,liver,gallbladder,spleen).

I.bellicancausesevereclinicalsymptoms,especiallyinAIDSpatients,forexample

persistentdiarrhea,steatorrhea,cholecystitis,weightloss,andfever.Diagnosisis

madebydetectionofunsporulatedoocysts(20– 30 lmlong)instool(Fig.9. 11 l,

p.504)orofdevelopmentalstagesinintestinalbiopsies.High-dosedcotrimoxazole

istherecommendedtherapy.

Cyclosporacayetanensis

Causativeagentofcyclosporosis

Parasiteandoccurrence.Cyclosporacayetanensiswasfirstidentifiedasan

apicomplexanparasite(familyEimeriidae)in 199 4.Theparasiteoccursinvar-

iouscountriesonallcontinentswithgenerallylowprevalencesandwithsea-

sonalfluctuations,inchildrenandadults,andalsoinAIDSpatients.

Morphologyandlifecycle.Infectionperoswithsporulatedoocystsinfoodor

drinkingwater.Developmentalstagesinduodenalandjejunalenterocysts,

probablytwogenerationsofschizonts;followinggamogonyformationof

sphericaloocysts 8 – 10 lminsize.Prepatencyaboutoneweek;oocystsare

shedunsporulatedinfeces,thensporulateoutsideofhostwithinfiveto

12 daystobecomeinfective.Thesporulatedoocystscontaintwosporocysts

withtwosporozoiteseach(Fig.9. 11 j,p. 50 4).

Clinicalmanifestations.Villusatrophy,cryptichyperplasia,andinflamma-

torychangesintheintestinalmucosa.Incubationaboutoneweek,self-limit-

ingdiarrheainimmunocompetentpersons(lastsforabouttwotothree

weeks)withlossofappetite,flatulence,andmalaise,usuallynonfebrile;

thediarrheamaypersistformonthsinimmunodeficientpatients.

Cyclosporacayetanensis 515

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Kayser, Medical Microbiology © 2005 Thieme