Parasite’s accomplice gets genetic mug

As many as 500,000 people per year in sub-Saharan Africa contract sleeping sickness, which can cause severe, irreversible damage to the nervous system. The illness is transmitted by blood-sucking tsetse flies, but only when they are themselves infected by the protozoan parasite Trypanosoma brucei, which is passed into humans when the tsetse bites.

In addition to T. brucei, the tsetse gut is also host to two so-called good bacteria that manufacture nutrients not found in the fly’s blood diet but crucial to its survival. In a joint project with colleagues in Japan reported online in the February issue of Genome Research, Professor of Epidemiology Serap Aksoy, Ph.D., sequenced the complete genome of Sodalis, a beneficial bacterium passed on by tsetse mothers to their larvae.

The new sequence will allow scientists to better manipulate the functions of Sodalis to gain insights into tsetse biology that could lead to novel ways to fight sleeping sickness, Aksoy says. “If we get rid of these symbiotic bacteria, the flies become sterile. Understanding what they provide to the flies is very important from a vector-control point of view.”