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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #71604
Title: THE IMPORTANCE OF INTESTINAL MICROFLORA IN CRYPTOSPORIDIUM PARVUM INFECTION

Author
item Harp, James

Submitted to: European Journal of Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Cryptosporidium parvum is a protozoan parasite that is a significant cause of diarrhea in humans and domestic livestock. At present, there are no effective treatments for C. parvum. In this paper, evidence is presented that intestinal bacteria are important in resistance to C. parvum. We show that mice without intestinal bacteria were susceptible to infection with C. parvum, while mice with intestinal bacteria were resistant. This was true for mice with both normal and deficient immune systems. We further show that giving beneficial strains of bacteria (such as those used to make yogurt) to mice without intestinal bacteria restored their resistance to C. parvum infection. These results suggest that the lack of intestinal bacteria in newborn animals, such as baby calves, may contribute to their susceptibility to this parasite. Treatment of animals with beneficial strains of bacteria may offer a safe and effective relief from intestinal disease due to C. parvum. This will reduce economic losses to producers and decrease the threat to human health caused by C. parvum.

Technical Abstract: Cryptosporidium parvum is a protozoan parasite that causes enteric infection and diarrheal disease in a wide variety of mammalian hosts. In recent years, C. parvum has been recognized as a significant cause of diarrhea in both humans and economically important livestock species. Cryptosporidium parvum is now the most commonly reported etiologic agent isolated from diarrheic calves in the United States. In a recent survey of 1,103 dairy herds, 48% of the calves between 7 and 21 days of age were infected with C. parvum. Recently, there have been a number of outbreaks of waterborne human cryptosporidiosis, the largest of which was in Milwaukee, Wisconsin, where >400,000 people were affected. Though not definitively shown, it has been suggested that infected cattle contaminating watershed areas may be a source of waterborne human cryptosporidiosis. These outbreaks demonstrate the importance of cryptosporidiosis as a zoonotic disease. Cryptosporidium parvum is infective for man, livestock, rodents, and other mammalian hosts.