AUTHORS:

Lea Berrang-Ford, James Ford, Barry Smit, David Waltner-Toews, John McDermott

ABSTRACT
Diseases often vary over space and through time. The understanding of causal relationships of disease risk can benefit from characterization of the spatial and temporal processes contributing to disease variation. This paper offers a framework for explicitly conceptualizing spatial and temporal relationships in the case of sleeping sickness in south-eastern Uganda. We identify broad categories of sleeping sickness determinants at multiple scales, and the main interactions over scales, space and time. In doing so, we highlight the role of both biological and social factors and their interactions, including the importance of civil conflict and political unrest, in the occurrence of sleeping sickness epidemics. The framework is used to conceptualize causal processes for sleeping sickness in south-eastern Uganda, including potential determinants of spatial variation (land cover change, and human and cattle host densities) and of temporal variation (social conflict). Conceptual approaches such as the framework used here can provide a structure for the synthesis and interpretation of existing research, as well as a guide for future research.