Cryptosporidium in Veterinary Students

Key Instruction Points

  • Treat all research animals as if they may have zoonotic disease

  • Practice good personal hygiene for prevention of disease

  • Work restrictions may be appropriate for immunocompromized persons – physician review is advised

A veterinary college obtained seven Holstein calves from two local dairies for a student laboratory. Thirty-five students worked with the calves in a lab session before the instructor learned that all of the animals were infected with Cryptosporidium. Subsequently, 8 of the students developed gastrointestinal illness. Cryptosporidium oocysts were found in fecal samples of half of the students tested. The affected students experienced fever, headache, nausea, diarrhea and vomiting. Most of the students recovered quickly with no treatment although one had severe diarrhea for two weeks and another required hospitalization for severe dehydration.

Cryptosporidium is a zoonotic, protozoan parasite which is similar to coccidia. It is almost ubiquitous in young ruminants (e.g. calves, kids, lambs). In people with a normal immune system it generally causes short-term diarrhea. In people with immunocompromised immune systems (e.g. from AIDS or cancer chemotherapy), it causes a prolonged, life- threatening disease. In 1993, when it contaminated the Milwaukee, Wisconsin water supply it caused widespread disease. There is no effective treatment known.

Practice good personal hygiene when working with young animals, especially calves. Cryptosporidium persists in the environment and can be spread by contaminated clothing. Infants and immunocompromised adults should not handle animals who have diarrhea. It is strongly recommended that immunocompromised persons should not work with calves, lambs, kids or deer fawns.