Host Parasite Interactions of Cryptosporidium

Our research is focused on the apicomplexan parasite Cryptosporidium which is a significant cause of diarrheal disease worldwide. Cryptosporidiosis is asymptomatic or self-limiting in immunocompetent hosts but may be severe, chronic and life threatening in immunocompromised patients, such as those with acquired immunodeficiency syndrome (AIDS). Several outbreaks of waterborne cryptosporidiosis have been reported worldwide. Because of the potential for intentional contamination of water supplies, Cryptosporidium is listed as a Category B Priority Pathogen for Biodefence. There are 2 main Cryptosporidium species that cause human infections; C. hominis primarily infects humans whereas C. parvum infects humans as well as other animals. Nitazoxanide is the only drug approved in the USA by the Food and Drug Administration for use in immunocompetent individuals with cryptosporidiosis. However, this drug is not effective against cryptosporidial infection in immunocompromised hosts. Therefore the continued search for novel therapeutic interventions is critical.

The pathogenic mechanisms by which C. parvum causes disease are unknown. In addition, little is known about specific parasite and host molecules involved in host-parasite interactions or about protective innate and adaptive immune responses. Our overall goal in the study of cryptosporidiosis is to further our understanding of the molecular basis of Cryptosporidium -host cell interactions and to investigate immune responses to this parasite. Understanding the molecular mechanisms underlying the host-parasite interaction may lead to the development of specific interventions targeted at inhibiting this interaction. Identifying the mechanisms underlying protective immunity could lead to the development of immune-based preventive and therapeutic anti-cryptosporidial strategies