Sleeping sickness surveillance: an essential step towards elimination.

In the last decades, with little or no surveillance sleeping sickness has returned to alarming levels comparable to the early twentieth century. Sixty million people are considered at risk but only 3-4 million are under surveillance, yielding some 45 000 new cases annually. It is estimated that at least 300 000-500 000 people are presently infected. Despite the almost universal presence of the vector in sub-Saharan Africa and the existence of an animal parasite reservoir, it is technically feasible to control and eliminate the disease as a public health problem. The authors describe, step-by-step, a surveillance method based on the epidemiological status of the village and using several approaches ranging from passive to active surveillance. Co-ordinated by the WHO, such surveillance has been incepted in several countries. Epidemiological data is spatially linked to the village, whose geographical co-ordinates are collected using a Global Positioning Systems (GPS). Information is transmitted to WHO through internet. Data analysis and mapping is carried out using Geographical Information System (GIS) software and thematic maps are generated to illustrate epidemiological status. Examples from Central African Republic (CAR), Cameroon and Gabon illustrate the process and mapping.