MORTALITY-RATES AND POPULATION-DENSITY OF TSETSE-FLIES CORRELATED WITH SATELLITE IMAGERY

TSETSE flies are a major constraint on animal production in about 10 million km 2 of Africa through their transmission of animal trypanosomiasis 1. Up to 25 million people are at risk from human trypanosomiasis, or sleeping sickness 2. Tsetse research has been concentrated on the factors that control the distribution and abundance of these vectors and the means by which their numbers can be reduced 3. Eradication successes in some countries are insignificant compared with the continental scale of the problem and the long-term reduction in the area infested by tsetse has been negligible 4. We report here that the mortality rates of tsetse from sites in both West and East Africa, the size of male and female tsetse (related to the mortality rate of the parental female population) along a north-south transect in West Africa, and the abundance of two species of tsetse over the northern half of Cote d'lvoire, are significantly correlated with data from meteorological satellites. This information could be used to predict both the mortality rate and the abundance (key determinants of disease transmission potential) of tsetse over very large areas of the continent and to produce maps of high risk areas of disease transmission for the African trypanosomiases and, by implication, for many other vector-borne diseases.