Geographical information systems for studying the epidemiology of cattle diseases caused by Theileria parva

Data on selected variables which influence the epidemiology of cattle diseases caused by Theileria parva were assembled and entered in a computerised geographical information system. Variables studied included the distributions of major hosts (cattle and buffalo), the vector ticks (Rhipicephalus appendiculatus and related species) and the reported presence of East Coast fever, corridor disease and January disease. In addition, the distribution of climatic suitability for R appendiculatus was assessed using the model CLIMEX run on an interpolated climate database developed for Africa. Distribution maps of each variable were produced. The potential value of geographical information systems in studies of disease epidemiology and control is discussed, with examples of how sensitivity may be enhanced by the inclusion of additional variables. In addition, subject areas in which poor data quality and inadequate data standardisation may limit the use of these systems are identified and discussed.