In 1995, the World Health Organization estimated 60 million people in rural Africa were at risk of a disease known as “sleeping sickness.” Though the number of cases has dropped from an estimated 30,000 that year to below 8,000 in 2010, the often fatal, and underreported, disease still poses a threat to many who can’t afford to seek care once infected. With no drugs specifically developed to combat this disease, efforts to try to stop the spread remain critical and primarily focus on controlling transmission.

Though international efforts have seen a drop in the number of sleeping sickness cases, the threat remains very real for a large number of people. A parallel wasting disease in cattle, known as Nagana, causes significant economic burden to several African countries further impeding economic and agricultural development.

Rita Rio, associate professor of biology at West Virginia University, has been awarded approximately $1.1 million by the National Institutes of Health and the National Institute of Allergy and Infectious Diseases to better understand the relationship between the tsetse fly and the parasite that spreads the disease.

African trypanosomes — the agent that causes these fatal diseases — is transmitted to humans and other animals through the infectious bite of the blood-feeding tsetse fly. The parasites Rio is studying flood the blood stream, replicate and evade the body’s natural defenses while causing significant detrimental health effects.

The tsetse fly serves as an insect carrier for the disease. While conventional wisdom dictates, “if you kill the fly, you kill the disease,” not all tsetse flies are competent carriers. Rio is studying how different metabolic contributions of the microbiota (other naturally occurring microbes that live in association with the tsetse) may facilitate parasite transmission. Manipulation of the microbiota offers exciting novel and specific targets for control strategies.”

“I think people are now appreciating there’s not a silver bullet out there for disease control,” Rio said. “We see the tsetse fly as an Achilles heel towards trypanosome biology, and manipulation of the microbiota may eventually enhance carrier control. By integrating these control mechanisms (along with pesticides, traps, education), you can tackle it from many different, yet complimentary avenues.”

African sleeping sickness is “recognized as one of the most neglected diseases in the world,” Rio said. Relative to other animals, tsetse flies have a limited microbiota, making it easier to tweeze apart host/microbe associations.

“We now know (microbiotas) exist and the available technology has enabled us to extend beyond asking who’s there but what they’re actually doing, and how they contribute to various health conditions” she said. “It’s a really great resource because it’s telling us about very important aspects of tsetse fly biology.”



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