After 10 years of effort, a team led by scientists at Yale has finally decoded the genes of the tsetse fly, a bloodsucking scourge of Africa.

With that knowledge, they hope to find new ways to repel or kill the insects, whose bite transmits sleeping sickness, a parasitic disease that, like rabies, drives its victims mad before they lapse into a coma and die. The flies also carry nagana, which weakens or kills cattle and renders whole regions of Africa inhospitable to most livestock.

There are now fewer than 10,000 confirmed cases per year of sleeping sickness — formally known as human African trypanosomiasis — but the disease occurs in epidemics. As recently as 1998, the number of estimated cases was 300,000. Treatment is long and difficult, and without it, the disease is always fatal.

Sequencing the genome of Glossina morsitans, one of several tsetse species, took a decade, partly because tsetses have highly unusual biology — they are the only insects that nurse their young, among other traits — and partly because of global health politics.