Cattle diseases caused by the protozoan parasite <i>Theileria parva</i> and transmitted by the brown ear tick <i>Rhipicephalus appendiculatus</i> are among the most costly diseases in eastern, central and southern Africa. The control of these diseases in areas where they occur, and the prevention of their spread to areas suitable for the survival and development of the vector, should be based on a strong understanding of their epidemiology. Therefore, methods to assist in transforming epidemiological information into a format that will assist animal health planners are needed. Computerized geographic information systems (GIS) may offer such valuable methodology. The purposes of this study were to define, characterize and display on a geographic basis, factors governing the epidemiology of cattle diseases caused by I parva. Factors studied included the distributions of the vector ticks (R appendiculatus and related species), major hosts (cattle and addition, continental representation of climatic parameters and satellite derived vegetation data were included. The c1imatedatabaseswereproducedusingmathematicalinterpolations of data from meteorological stations and further improved by the incorporation of an altitude data set. Interpolated climate databases were then used to run a climate matching model (CLIMEX)l to define areas of climatic suitability for tick distribution and abundance. A computerized geographic information system was used to store, manipulate, analyze buffalo) and display the data. / Ph. D.