Etiology:  Cryptosporidium muris and Cryptosporidium parvum are one celled, eukaryotic organisms.

Incidence: Incidence of infection is rare.

Transmission: Transmission occurs by ingestion of infective cyst.

Distribution:

C. muris: stomach

C. parvum: small intestine

Clinical signs: Clinical signs range from none to mild enteritis. Clinical signs can be severe in young animals with heavy parasite loads.

Diagnosis:

Antemortem: Antemortem diagnosis is difficult.  A fecal smear can be examined for oocysts.

Diagnostic morphology:

C. muris oocyst: 7 x 5 µm

C. parvum oocyst: 4-5 x 3 µm

Postmortem: Diagnosis can be made by histopathologic examination of the small intestine. Organisms can be identified within the brush border of intestinal enterocytes (arrow, A.).