Cryptosporidium

CRYPTOSPRORIDIUM

SOIL MICROBIOLOGY

BIOL/CSES 4684

This webpage was created by Jillian Campbell

1. IDENTIFYING CHARACTERISTICS

Parasites - hosts include fish, reptiles, poultry, and humans
Form spores called oocysts
Asexual and sexual reproductive phases
Unusually resistant to natural stresses and man-made chemicals
Lack mitochondria and micropores
Protozoa
Locomotion - flexing, gliding
Referred to as coccida

The above picture is of cryptosporidium spores attached to the epithelial cells of the intestine.

2. TAXONOMIC DESCRIPTION

Classification

Empire - Eukaryota

Kingdom - Protozoa

Phylum - Apicomplexa

Class - Coccidea

Order- Eucoccidiorida

Family - Cryptosporidiidae

The above picture is of cryptospordia oocyts in a stool sample.

Cryptosporidium is one of several protozoan in the Apicomplexa phylum. Some must develop in the gastrointestinal tract of vertebrates such as humans, farm animals, household pets, etc., while others are capable of extraintestinal development. There are 8 named species and several unconfirmed species. Many of the species were named after the host in which they were found. For example, C. felis was discovered in the intestine of domestic cats. The most well-known species is C. parvum, which is a severe waterborne pathogen that causes cryptosporidiosis, a flu-like intestinal disorder (see below for details).

3. ISOLATION AND ECOLOGY

Cryptosporidium is commonly found in surface waters that have been contaminated by the feces of infected hosts, which contain Cryptosporidium occysts. Such environments include lakes, rivers, and streams. In the past, it has been difficult to enumerate the parasite using standard methods, especially C. parvum, which is of the most concern. For this reason, there has been a surge in research on such methods. Bennett et al. (1999) examined several different methods and found flow cytometry to be the most favorable. Flourescent staining is often used after enumeration in order to preserve the occysts.

4. CRYPTOSPORIDIOSIS

Cryptospordiosis is the disease caused by C. parvum, a pathogen found in water systems. The first case of cryptosporidiosis was reported in 1976, but a national focus on the disease has just begun in the last decade due to a severe outbreak of cryptosporidiosis in Milwaukee, Wisconsin in 1993. Over 400,000 cases of intestinal disease were reported during this outbreak alone. Several outbreaks have occured in the U.S. because of infected drinking water supplies, but the one in Milwaukee was by far the most severe. The drinking water becomes polluted by sewage runoff containing Cryptosporidium occysts, which are resistant to chlorination, a common method of water treatment. The symptoms of cryptosporidiosis include diarrhea, stomach cramps, and a slight fever. An infected person with an otherwise healthy immune system is likely to be affected for approximately two weeks; however, those with weakened immune systems, such as HIV/AIDS patients, can be significantly more affected.

5. ADDITIONAL SOURCES OF INFORMATION

Bennett, J.W., Gauci, M.R., Le Moenic, S., Schaefer III, F.W., Lindquist, H.D.A. 1999. A comparison of enumeration techniques for Cryptosporidium parvum occysts. J. Parasitol. 85(6):1165-1168.

Fayer, R. ed. 1997. Cryptosporidium and Cryptospordiosis. CRC Press LLC, Boca Raton, FL. pp. 251.

Madigan, Michael T., Martinko, John M., and Parker, Jack 2000. Brock Biology of Microorganisms. Prentice-Hall, Inc., Upper Saddle River, NJ. pp. 991.

6. LINKS TO OTHER SITES ON CRYPTOSPORIDIUM

http://www.ksu.edu/parasitology/ - practically everything you would want to know about Cryptosporidium

http://www.cellsalive.com/parasit.htm - a comprehensive site, with images