Medical Microbiology

Diagnosisandtherapy.Detectionofoocystsinstoolspecimensusingcon-

centration methodsor instained stool smears(forinstance modified

Ziehl-Neelsen stainingor modified carbol-fuchsin staining).Cyclospora

oocystsareeasilyconfusedwiththeoocystsofcryptosporidia(Fig.9. 14 );

theyshowautofluorescenceinUVlightandnoreactionwithmonoclonal

antibodiestoCryptosporidium.Thedrugofchoiceiscotrimoxazole.

Sarcocystis

Causativeagentofsarcocystosis

Parasites,lifecycle,andepidemiology.SarcocystishominisandS.suihominis

areknownashumanintestinalparasites.Infectionresultsfromingestionof

raworinsufficientlyheatedmeatfromcattleorpigs,whichfrequently

containsmusclecystsofthesespecies.Inthesmallintestine,bradyzoites

arereleasedfromthemusclecysts.Thebradyzoitesundergogamogony

withoutanasexualreproductivephaseinthelaminapropriaoftheintestine.

Thisprocessproducesthin-walledoocyststhatsporulateintheintestinal

wall.Oncethefrailoocystwallhasburst,freesporocystscontainingfour

sporozoiteseachareexcretedwithstoolinmostcases.Thesporozoites

are infectiousfor intermediate hosts. Prepatent periodsof 14 – 18 and

516 9 Protozoa

CyclosporaandCryptosporidium

a^10 μm b^10 μm c^10 μm

Fig.9. 14 a OocystsofCyclosporacayetanensisinstoolsmear,modifiedZiehl-

Neelsenstaining.bOocystsofCyclospora,unstained,afterisolationfromstool.

cOocystsfromCryptosporidiumparvuminstoolsmear.Stainingasina. (band

cfrom:BenchAidsfortheDiagnosisofIntestinalParasites.Geneva:WHO; 1 995.)

9

Kayser, Medical Microbiology © 2005 Thieme