Between 1976 and 1983 in the Busoga Region in Uganda 10,414 male and 9,560 female patients were detected with trypanosomiasis. Prior to the onset of the epidemic, Glossina f. fuscipes, the sole vector, had broken through the tsetse control barrier and had spread to cover most of the region. The fly was further observed to be resting in Lantana plants and coffee and banana plantations which are widespread in the area. A close and regular contact was thus established between man and fly. It was observed that the young and engergetic persons first became infected, but as the epidemic unfolded the older age-groups bore the brunt. The infection was also seen in all other age-groups indicating the closeness of contact between the fly and the local population.