A new hope is emerging for eliminating sleeping sickness, which, despite a significant decrease in the 20th century, remains a major concern in Sub-Saharan Africa and a neglected tropical disease. An international research team, including entomologists from IRD, Génoscope, and CIRDES, just published the DNA sequence for the tsetse fly in Science. The fly transmits the parasite to humans and pets through its bite. It took ten years of work by some 145 researchers in the consortium to reveal the genome of the vector fly, also called glossina. They also determined its genetic structure and the proteins coded by each gene. Knowing its genome is essential to understanding the biology of the tsetse.
A fly like no other
This information is of special importance for glossina. In fact, it is unique in biological terms. It is distinct from all other insects in many ways. First, contrary to other vectors among which only the female bites to feed on blood, both sexes are hematophagous. More surprising, the fly has a very distinctive reproductive method, comparable to that of mammals. It does not lay eggs but gives birth to developed larva after ten days gestation in its uterus, during which it feeds its offspring with a milky secretion! Access to its DNA represents a major scientific advance, and will accelerate research on its fundamental biology. It opens the way for new prospects for controlling this vector.
A neglected disease until now
Screening and treatment for sleeping sickness, or Human African Trypanosomaisis (HAT), is costly, difficult, and toxic. Preventing the disease by developing a vaccine seems difficult because of the ability of the trypanosome to thwart mammalian immune systems. Therefore, vector control is currently the only means of breaking the transmission cycle for the disease.
Gradually, HAT is becoming a less-neglected disease, mobilising an increasingly large scientific community through studies such as these. These studies should make new concrete progress possible for the disadvantaged populations that are the victims of this scourge.
Cite This Page: