[The epidemiology of human African trypanosomiasis: a complex multifactorial history].

Sleeping sickness has long been known from descriptions by Arab merchants and slave traders. However it was not until 1901 that Forbes discovered the offending agent and 1903 that Bruce described the role of the tsetse fly. The basic epidemiological transmission cycle was described less than 10 years later. Although the main outline of the original model can still be considered as sound, subsequent research has greatly expanded our knowledge. Molecular biology has identified different parasites causing clinical forms of varying severity. Understanding of the antigenic variability to the parasite has also improved. While available data is still insufficient on the relationship between the vector and human being and the vector and the animal reservoir, the behavior of glossinae is well-documented. Current geographical information systems have promoted understanding of the distribution of the disease to enhance targeting of screening, treatment, and vector-control activities. To repeat the success achieved in controlling the disease in endemic countries in the 1960s, it will be necessary to develop new strategies based on this new knowledge.