Results of the study will appear in the March 15 issue of Proceedings of the National Academy of Sciences. Scientists identified the new protein in the protozoan parasite Toxoplasma, which epidemiologists estimate infects 25 percent of all humans. The parasite rarely causes symptoms in most people, but can become a potentially life-threatening infection when the immune system is weakened by illnesses such as HIV or is suppressed to facilitate an organ transplant.
"Toxoplasma is like a time bomb that can go off and cause serious trouble when the immune system wanes or is compromised," explains L. David Sibley, Ph.D., professor of molecular microbiology at Washington University School of Medicine. For the study, researchers in Sibley's lab collaborated with Sinisa Urban, Ph.D., assistant professor of microbiology at Harvard University.
Sibley's lab studies Toxoplasma both because of the threat it poses to patients and for the potential insights it can offer into other apicomplexan parasites, which include malaria and Cryptosporidium. Malaria, which is spread by mosquito bites, kills at least 1 million people per year through damage to red blood cells and clogging of the capillaries that feed the brain and other organs. Cryptosporidium, which causes diarrhea, vomiting and other symptoms, is one of the most common causes of water-borne disease in the world.
"These other parasites are more devastating in terms of the number of people they affect, but they're somewhat harder to work on," Sibley explains. "Because it's so much easier to study, we use Toxoplasma as a way to ask about very basic
Source:Washington University in St. Louis