RESUMO
In the Congo the Sangha focus of sleeping sickness caused more than 500,000 deaths in the early 20th century. Despite many years of quiescence many new cases have been detected since the early eighties. In 1987 an investigation found 43 infected patients within 5 villages (during the same year, 74 cases were detected from both investigation and passive detection). In December 1989 our further investigation found 96 new documented cases (115 for the whole year). The prevalence is increasing and the proportion of early stage in comparison with later stage is decreasing. The age diagram resembles that of the early 20th century. Despite the fact that the survey in 1989, extracted twice as many patients as in 1987 passive detection detected 99 infected patients in 1990, three times as many cases as in 1988, and places the "Sangha focus" in IId place in the Congo, after the "Bouenza focus". As only river transport is available to have access to that focus, the Congo will be faced with considerable difficulties in the future.
