A PCR-based field evaluation of Theileria infections in cattle and ticks in Kenya

Theileria parva is a hemoprotozoan parasite responsible for causing East Coast fever in east and central Africa. The vaccine currently available is an "infection and treatment" procedure which involves the injection of live sporozoites followed by drug therapy to prevent clinical illness. Before introducing potentially new strains of parasite into an area, however, it is crucial to check the disease situation in the field first. We looked at three different areas in Kenya: Limuru in which many cattle have already been vaccinated and Kitale and Kakamega which so far have not been vaccinated. Genus and species specific primers were used to test for the presence of Theileria species in blood and tick samples collected from the three areas. Limuru showed a cattle and tick infection prevalence of 27% and 2.3% respectively with T. parva. Kitale showed a cattle and tick infection prevalence of 100% and 14.2% respectively while Kakamega showed 100% and 0% respectively. Reasons for variations between areas involving vaccination status and epidemiological data are discussed.