Crytosporidia :: Essays Papers

Crytosporidia Life History: Once thought to be rare and host specific, Cryptosporidia is now believed to be one of the top three diarrheal causing pathogens in the world. Cryptosporidia muris was recognized in 1907 by E. E. Tyzer. Since then twenty (20) species of Cryptosporidium have been discovered and named although recently sixteen (16) of those twenty (20) have come under speculation due to recent cross-transmission studies. Cryptosporidia is a protozoan parasite which lives in the intestines and respiratory epitheliums of many types of animals including mammals, birds and reptiles. The disease caused by Cryptosporidia is known as Cryptosporidiosis. Cryptosporidia is found all over the world and is transmitted via fecal oral contact. Usually this is due to water contaminated by animal feces. Infected calves excrete up to 10 billion Cryptosporidium oocysts (infectious stage) per day. The infectious dose in humans is only 10-100. However, contaminated food or direct contact with feces can also cause infectio n. Microbial Characteristics: Cryptosporidia are small coccidian spore-forming protazoans. When in oocyst form they are 4-6 um in size. GRAPH Disease: Cryptosporidia are encountered and transmitted through fecal oral transmission. Once a host ingests an oocyst, sporozoites are released. The sporozoite then can enter the epithelial cells in the small intestine where it will develop into a trophozoite. Inside of a trophozoite, merozoites begin to form. When released, a merozoite can either infect another epithelial cell or it can evolve into a sexual gamete. These gametes then join to form an oocyst and will be excreted in the feces. While in the host’s body, Cryptosporidia carries out its entire life cycle in the microvilli of the small intestine. The most common symptom of Cryptosporidiosis is watery diarrhea. Other symptoms include: - Dehydration - Weight loss - Stomach cramps or pain - Fever - Nausea - Vomiting Some people with Cryptosporidiosis will have no symptoms at all. While the small intestine is the site most commonly affected, Cryptosporidium infections could possibly affect other areas of the digestive or the respiratory tract. (CDC) Symptoms usually begin 2-10 days after becoming infected and last 1-2 weeks on average. In immunocompetent individuals, Cryptosporidiosis is not life threatening.