Cryptosporidiumand host resistance: historical perspective and some novel approaches

Abstract

AbstractCryptosporidium parvumis recognized as a major cause of diarrheal disease in neonatal bovine calves. In addition, this protozoan parasite has emerged as an important cause of disease in both immunocompromised and immunocompetent humans. Despite years of research, no consistently effective means of prevention or treatment are readily available for cryptosporidiosis in any species. Infection through ingestion of contaminated water has been widely documented;C. parvumwas reported to be responsible for the largest waterborne outbreak of infectious disease in US history. In addition to its role as a primary disease agent,C. parvumhas potential to initiate or exacerbate other gastrointestinal disorders, such as inflammatory bowel disease. Thus, control ofC. parvuminfection in both animals and humans remains an important objective. Research in our laboratory has focused on understanding mechanisms of resistance toC. parvum. We have demonstrated that acquisition of intestinal flora increases resistance toC. parvum.Substances present in the intestinal mucosa of adult animals can transfer resistance when fed to susceptible infants. Both expression of intestinal enzymes and rate of proliferation of epithelial cells may be altered followingC. parvuminfection. These and other changes may have profound effects on host resistance toC. parvum.