(Protozoan) Cryptosporidium parvum
Cryptosporidiosis was first recognized in 1907 by Edward Tyzzer
in the gastric glands of asymptomatic laboratory mice. For nearly 50
years after Tyzzer's initial discovery the protozoan was considered a
benign commensal organism. It was not until 1955, when
Cryptosporidiosis was discovered in fowl with fatal enteritis that
the protozoan was considered a parasite. Since the 1970s,
Cryptosporidiosis has been identified in the gastrointestinal or
respiratory tract of most species of animals, including mammals,
reptiles, birds and fish. Cryptosporidiosis has now entered the
forefront of public attention as it has become a lethal threat to
immunosuppressed individuals. In the case of HIV, cryptosporidiosis
plays the role of an opportunistic infection as it may cause severe
dehydration and malnutrition, which may be fatal to the HIV positive
The symptoms of a Cryptosporidia infection are diarrhea,
abdominal pain, weight loss, slight fever and nausea. These symptoms
usually manifest themselves in the individual within 2-10 days of
exposure to the parasite.
Cryptosporidiosis has a large reservoir, which includes
cattle, deer, mice, dogs, cats, and poultry. Cryptosporidia live in
the intestine of infected humans or animals. These parasites are
passed on through contact with infected feces or through contact with
contaminated water, food, soil. There is no documented animal vector
for this parasite.
The diagnosis of cryptosporidiosis is performed through
two methods: intestinal biopsy or examination of stool samples to
detect the oocysts.
The usual method of therapy is to allow the infection to
run its course. The patient is encouraged to ingest a lot of water in
order to combat the effects of diarrhea. The parasitic infection
usually disappears from the body of a healthy adult within at most
2 weeks. In the case of immunosuppressed individuals, pregnant women
and young children, there are several courses of therapy to speed up
the recovery process. The drugs paromomycin, azythromycin and
nitazoxonide are used as treatments, even though their efficacy
rates have not been impressive.
Contact with human and animal feces should be entirely avoided and if such interaction is necessary as in diaper changing, litter box cleaning, the individual should wear protective gloves. If contact occurs the individual should immediately wash and disinfect exposed area. Ingestion of water from rivers, lakes, swimming pools or other such open bodies of water should be avoided. Water used for drinking should be filtered or boiled for at least 1 minute.