Cryptosporidium spp. (Pathogen)
Internal autoinfection occurs, particularly in the compromised patient; immunocompetent patients tend to self cure over a period of a few weeks.
Fecal-oral transmission via oocyst form; contaminated food and water
Worldwide, primarily human-to-human transmission, also animal-to-human transmission
Intestinal: Intermittent diarrhea (5-10 watery, frothy bowel movements per day), nausea, low-grade fever, abdominal cramps, anorexia; some may have relatively few symptoms.
Extraintestinal: Immunocompromised patients cannot self-cure; the illness is chronic and becomes progressively worse, and the sequelae may be a major factor leading to death.
Once the primary infection has been established, the immune status of the host plays a very important role in determining the length and severity of the illness.
Intestinal: Stool, examination of mucosal surface (biopsy)
Extraintestinal: Fluids, biopsy specimens
Intestinal: Ova and Parasite examination (concentration ONLY); from concentrate sediment, (500 x g for 10 min) modified acid-fast stains are performed. Fecal immunoassays are also available (FA, EIA, immunochromatographic cartridges). Multiple fecal examinations may be required to recover the organisms, particularly if the stools are formed; there is a direct relationship between the stool consistency and the number of oocysts present (diarrhea = more oocysts).
Extraintestinal: Modified acid-fast stains
Tissue: Found at all levels of the intestinal tract, with the jejunum being the most heavily infected site. Routine H&E staining is sufficient to demonstrate the organisms. Under regular light microscopy, the organisms are visible as small (~1 – 3 µm) round structures aligned along the brush border (intracellular, but extracytoplasmic and found in parasitophorous vacuoles).
Oocyst: Round oocysts, containing 4 sporozoites. However, sporozoites are not always seen in every oocyst; the oocysts are immediately infectious when passed (even if sporozoites are not visible).
Tissue: Oocysts (~1 – 3 µm) can be seen aligned along the brush border (intracellular, but extracytoplasmic and found in parasitophorous vacuoles).
Garcia, L.S. 2007. Diagnostic Medical Parasitology, 5th ed., ASM Press, Washington, D.C.
Although a number of drugs have been tested, none are totally effective.
Improved hygiene, adequate disposal of fecal waste, adequate washing of contaminated fruits and vegetables; prevention of human-animal contact, particularly cattle