Intestinal Sporozoans Clinical Microbiology Review 244
ORGANISM TRANSMISSION DIAGNOSIS OTHER
Isospora belli
Cryptosporidium parvum
Cyclospora cayentanensis
Microsporidia
Human is definitive host. Causes anorexia,
nausea, abdominal pain, diarrhea, possi-
ble malabsorption.
Important opportunistic infection in AIDS
patients. Causes chronic diarrhea in
immunosuppressed, acute self-limited
diarrhea in immunocompetent.
Prolonged diarrhea.
Obligate intracellular parasites. Oppor-
tunistic pathogens, mainly in AIDS
patients. Cause prolonged diarrhea.
Can disseminate. Molecular studies indi-
cate related to fungi.
Ingestion of oocysts in
fecally contaminated
food or water
Ingestion of oocysts from
food or water contami-
nated with animal feces,
oral/anal route, direct
contact with infected
individual or animal
Contaminated food &
water
Ingestion of spores
Oocysts in feces. 30 × 12 μm.
Transparent. 1–2 sporoblasts.
Modified acid-fast stain of feces.
Red spherical bodies 3–6 μm.
4 sporozoites. Immunoassay kits.
Oocysts in direct wet mount.
8–10 μm. Variable staining with
modified acid-fast stain. Autoflu-
orescence under UV light. Bright
blue at 365 nm, mint green at
450–490 nm.
Chromotrope or calcofluor white
stain of formalin-preserved stool.
Spores are 1.5–4.0 μm.
