Risk factors assessment for T. b. rhodesiense sleeping sickness acquisition in S.E. Uganda. A case-control study.

The major risk factors associated with acquisition of T. b. rhodesiense sleeping sickness in the Busoga focus, S.E. Uganda were investigated using a case-control study. 122 cases and 244 matched controls were used in the study. For each case two age-, sex- and resistance controls (1 matched nearest neighbour control and 1 village control) were selected. Patients and controls answered the same questionnaire which had been developed and field tested before the field study started. A logistic regression model for a 1:2 matched case control design was fit to the data. The following factors were found significant: cases spent more time outside their village of residence than controls and visited more SS high risk areas than controls, more cases than controls collected firewood in the forests. Generally, cases had less domestic animals grazing near the places of man-fly contact, especially near water and firewood collecting and bathing points, and near farms and gardens, than controls. Cases had more antecedents of sleeping sickness in the family. Generally cases had a less well developed information network than controls, and belonged economically to a less powerful group. Based on these results we may conclude that the risk to develop T.b. rhodesiense sleeping sickness depends upon a multitude of economical, cultural and human behaviour factors. These factors should be taken into account in the planning and monitoring of sleeping sickness control programmes.