Human African trypanosomiasis (HAT) is caused by parasites and spreads through the bite of the tsetse fly. The disease can take months or more than a year to develop, first causing flu-like symptoms and then affecting the central nervous system. HAT can cause behavioral changes and disrupt sleep, leading to aggression and other symptoms. If left untreated, it is almost always fatal. Because there is no vaccine to prevent the disease, eradication efforts usually focus on controlling tsetse flies and preventing fly bites.
The disease occurs in two forms, named after the type of parasite that causes the disease. The gambiense form is the most common, accounting for about 92 percent of cases. Togo, Benin, Ivory Coast, Uganda, Equatorial Guinea, Ghana and Chad have thus far eradicated the disease. The other variant, the rhodesiense form, has been eradicated in Rwanda.
HAT used to be much less common, with only 4,435 cases reported in Africa in 1964. But the disease reemerged in the second half of the 20th century as emerging African nations faced wars and political and social instability. In 1998, the WHO counted 37,991 new cases per year.
Chad has eliminated HAT with improved surveillance, testing and pest control, the WHO reported. “This achievement is the culmination of years of dedicated efforts by our health workers, communities and partners,” Abdel Modjid Abderahim Mahamat, Chad’s Minister of Health, said in the press release. “We will continue this momentum to address other neglected tropical diseases and ensure a healthier future for all Chadians.”