Cryptosporidium spp are coccidian parasites that are not host specific, are not susceptible to conventional anti-coccidial treatment and to date have no available efficacious specific chemotherapy. They are associated with gastrointestinal or respiratory disease, affecting particularly young animals. Ruminants, pigs, horses, mice, birds, and man are common hosts. Occasionally detected in young cats, dogs, rabbits, guinea pigs and other mammals, as well as in reptiles and fish.

Signs most commonly seen are anorexia and diarrhoea in calves, lambs, kids, piglets, foals and deer calves. Disease is spread by infectious oocysts which are shed in faeces or respiratory secretions, and have high environmental resistance. Host debilitation and/or concurrent viral or bacterial infection may predispose to infection. Immuno-compromised or immuno-incompetent animals are at high risk of infection.

Diagnosis

Identification of oocysts in faeces, by examination of faecal smears stained with acid-fast stains or by phase contrast microscopy of faecal floatations. Identification of organisms in the brush border of mucosal surfaces on histopathology. Antigen capture ELISA on faeces of calves (where available), although this technique may be less sensitive than microscopic examination.

Specimens required

1. Faecal sample for preparation of MZN-stained smears or floatations.
2. Formalin-fixed abomasum/stomach (peptic gland epithelium) and small intestine from freshly-killed mammals, reptiles or fish.
3. For birds, formalin-fixed small intestine, caecum, colon and bursa, or epithelium of the upper respiratory tract and lung from freshly-killed cases.