The Geographical distribution of the disease

Sleeping sickness threatens over 60 million people in 36 countries of sub-Saharan Africa. Only 3 to 4 million people at risk are under surveillance, with regular examination or access to a health centre that can provide screening.

Detection of the disease calls for major human and material resources, such as well-equipped health centres and qualified staff. Because such resources are lacking, most people with sleeping sickness die before they can ever be diagnosed.

· Almost 45 000 cases were reported in 1999, but the World Health Organization (WHO) estimates that the number of people affected is ten times greater. The 45 000 case figure shows not the true situation but rather the lack of screening in many foci. The real number of cases seems to be between 300 000 and 500 000. Reported cases in recent years are from countries where surveillance coverage is no more than 5%.

· In certain villages of many provinces of Angola, the Democratic Republic of Congo and southern Sudan, the prevalence is between 20% and 50%. Sleeping sickness has become the first or second greatest cause of mortality, ahead of HIV/AIDS, in those provinces.

Countries are placed in four categories in terms of prevalence. In each country the spatial distribution of the disease is very diverse; it is found in foci and micro-foci.

· Countries where there is an epidemic of the disease, in terms of very high cumulated prevalence and high transmission: Angola, Democratic Republic of Congo and Sudan;

· Highly endemic countries, where prevalence is moderate but increase is certain: Cameroon, Central African Republic, Chad, Congo, Côte d'Ivoire, Guinea, Mozambique, Uganda and United Republic of Tanzania.

· Countries where the endemic level is low: Benin, Burkina Faso, Equatorial Guinea, Gabon, Kenya, Mali, Togo and Zambia;

· Countries whose present status is not clear: Botswana, Burundi, Ethiopia, Liberia, Namibia, Nigeria, Rwanda, Senegal and Sierra-Leone.