“In the young, the elderly and immunocompromised people such as people infected with HIV/Aids, C. parvum is a very dangerous pathogen. Cryptosporidiosis is potentially life-threatening and can result in diarrhea, malnutrition and muscle loss and body mass wasting,” says Dr. Momar Ndao, Director of the National Reference Centre of Parasitology (NRCP) at the MUHC who is also an Assistant Professor of the Departments of Medicine, Immunology and Parasitology at McGill University, and first author of this new study.
The oocysts of C. parvum, which are shed during the infectious stage, are protected from a thick wall that allows them to survive for long periods outside the body as they spread to a new host. C. parvum is a microscopic parasite that lives in the intestinal tract of humans and many other mammals. It is transmitted through the fecal-oral contact with an infected person or animal, or from the ingestion of contaminated water or food. Since the parasite is resistant to chlorine and difficult to filter, cryptosporidiosis epidemics are hard to prevent.
“Most protozoan (single-celled) parasites like C. parvum use enzymes called proteases to escape the body's immune defenses,” explained Dr. Ndao, who is also a researcher in the Infection and Immunity Axis of the RI-MUHC. “In this study, we were able to identify a protease inhibitor that can block the parasite's ability to circumvent the immune system, and hide in intestinal cells called enterocytes, in order to multiply and destroy the intestinal flora.”
The discovery, which was made in collaboration with US researchers, is the first time a molecular target has been found for the control of C. parvum. “The next step will be to conduct human clinical trials to develop an effective treatment for this parasite, which affects millions of people around the world,” concludes Dr. Ndao.
Useful links :
- Cited study: http://aac.asm.org/content/early/2013/09/17/AAC.00734-13.abstract
- Public Health Agency of Canada: http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/msds48e-eng.php
- Bioterrorism Agents/Diseases (CDC): http://emergency.cdc.gov/agent/agentlist-category.asp
The National Reference Centre for Parasitology (NRCP) based in the Research Institute of the MUHC is an external reference laboratory for Health Canada whose objective is to evaluate and develop tests for parasitic diseases, provide reference tests providing highest diagnosis, epidemiological studies on human parasitic diseases and teaching as well as research related to parasitic diseases affecting Canadians. www.nrcp.ca