Due to the tsetse fly's climatic restrictions the disease is restricted between the 14th latitude north and the 29th latitude south on the African continent (Molyneux 1983). According to the World Health Organization in 2001, countries where the disease is currently epidemic include Angola, Democratic Republic of the Congo, Uganda & Sudan. Countries with high levels of this disease are Cameroon, Congo, Cote d"Ivoire, Central African Republic, Guinea, Mozambique, Tanzania, & Chad. African sleeping sickness can also be found in low endemic levels in Benin, Burkina-Faso, Gabon, Ghana, Equatorial Guinea, Kenya, Mali, Nigeria, Togo, & Zambia. Because of poor disease surveillance and reporting, epidemiological information in Burundi, Botswana, Ethiopia, Liberia, Namibia, Rwanda, Senegal, & Sierra-Leone is poorly understood.
Sleeping sickness is a daily threat to more than 60 million men, women and children in 36 countries of sub-Saharan Africa, 22 of which are among the least developed countries in the world. However, only 3 to 4 million of these people are under surveillance and the 45,000 cases reported in 1999 do not reflect the reality of the situation, but simply show the absence of case detection. The estimated number of people thought to have the disease is between 300,000 and 500,000. In Uganda two thirds of all deaths are cause by sleeping sickness. Most people with sleeping sickness die before they can ever be diagnosed (WHO, 2001).
The disease is transmitted with the bite of the tsetse fly. At first the trypanosomes multiply in the blood, and that process can last for years. In a mother-to-child infection the trypanosome can cross the placenta and infect the fetus, causing abortion and prenatal death. .
After a person is bitten by an infected fly, symptoms such as a red painful swelling develops at the site of the fly bite. From this site of injection, the parasite invades the blood stream causing episodes of fever, headache, sweating, and enlargement of the lymph nodes.
