Scientists Identify Weak Spot in a Parasite's Armor

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NIGMS Communications Office

Human African trypanosomiasis, known as sleeping sickness, is caused by infection with the parasite Trypanosoma brucei. Tsetse fly bites transmit this parasite to humans and livestock, where it feeds on blood. In an infected person, the parasite spreads throughout the entire body, causing at first high fever, weakness, headaches, joint pain, and itching. Over time, symptoms become more severe. People with sleeping sickness experience periods of sleeplike unconsciousness that are followed by coma and death. Although the incidence of sleeping sickness had declined dramatically by the mid-1900s, reduced screening and surveillance have led to new epidemics of the disease over the last 30 years. T. brucei's complicated life cycle, like that of many parasites, has limited the success of both prevention and treatment.

Recently, scientists discovered a new weak spot in the armor of the parasite T. brucei. Researchers already knew that enigmatic molecular processing events called "RNA editing" took place in both the life-cycle form of T. brucei living in tsetse flies and in the bloodstream form of this parasite. Now, Dr. Kenneth Stuart of the Seattle Biomedical Research Institute has determined that RNA editing is an essential process for survival of the bloodstream parasite. 1 In the course of their studies, Dr. Stuart and his coworkers also found a way to thwart the growth of the bloodstream form of T. brucei by knocking out one of the enzymes that performs the RNA editing and that is critical to its metabolism.

Dr. Stuart's findings point to a potential new way to treat sleeping sickness by targeting the essential RNA editing function of the bloodstream form of T. brucei. By demonstrating that the enzyme that carries out the crucial RNA editing function is absolutely necessary for the survival of the bloodstream form of the parasite, the new work holds promise for enabling scientists to design targeted medicines to kill the parasite.


1 Shnaufer A, Panigrahi AK, Panicucci B, Igo Jr. RP, Salavati R, and Stuart K. An RNA ligase essential for RNA editing and survival of the bloodstream form of Trypanosoma brucei. Science 2001;291:2159-62.

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Writer: Alison Davis, Science Writing Contractor