Skip Navigation

NIAID Archive

Important note: Information on this page was accurate at the time of publication. This page is no longer being updated.
NIH HHS News Release Logo
National Institute of Allergy and
Infectious Diseases (NIAID)

Friday, March 26, 2004

Media Contact:
Jennifer Wenger
(301) 402-1663
Skip Content Marketing
  • Share this:
  • submit to facebook
  • Tweet it
  • submit to reddit
  • submit to StumbleUpon
  • submit to Google +

Genome Sequence Reveals Leaner, Meaner Intestinal Parasite

Cryptosporidium parvum-an insidious, one-celled, waterborne parasite that lodges in the intestines of infected people and animals and for which there is currently no effective treatment-is missing key structures normally found in similar parasites, say researchers supported by the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health. The results of their genome sequencing project, now available in the online issue of Science, could help scientists home in on new drug targets that may lead to therapies for the disease.

C. parvum is an extremely hardy parasite found in water supplies throughout the world, including the United States. In persons with healthy immune systems, symptoms of infection include diarrhea, stomach cramps, upset stomach and fever. For persons with weakened immune systems, however, such as individuals with HIV/AIDS, symptoms may be more severe and can lead to serious or life-threatening illness. Because C. parvum could potentially be used as a bioterrorist agent, the NIAID has classified it as a Category B priority pathogen.

After reconstructing the predicted genes and resulting proteins of one form of C. parvum, researcher Mitchell S. Abrahamsen, Ph.D., University of Minnesota, St. Paul, MN, and his team discovered that Cryptosporidium is missing two organelles commonly found in related protozoan parasites. Gone is the apicoplast, a cellular component that provides essential metabolic functions in related parasites, including those that cause malaria and toxoplasmosis, respectively. Also absent is the mitochondrion, the so-called "energy factory" found in the cells of most plants, animals, fungi and one-celled organisms. In addition, the researchers found that Cryptosporidium has significantly fewer genes than related parasites, and, as a result, can carry out fewer metabolic functions on its own.

Because Cryptosporidium has been so difficult to study up until now-presumably because its demands for energy and nutrients have made it virtually impossible to grow in the laboratory-the decoding of the genome sequence provides valuable opportunities to inform and study the organism's biology. And with an understanding of its biology, researchers are better positioned to find treatments that zero in on unique biological processes essential for the organism's survival.




MS Abrahamsen et al. Complete genome sequence of the apicomplexan, Cryptosporidium parvum. Science DOI: 10.1126/science.1094786 (published online March 25, 2004).

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

NIH...Turning Discovery Into Health ®

back to top


NIAID Archive

Important note: Information on this page was accurate at the time of publication. This page is no longer being updated.

Last Updated March 26, 2004