Theileria parva seroprevalence in traditionally kept cattle in southern Zambia and El Niño

Sero-epidemiological surveys involving 27,526 cattle over a period of 8 years show that Theileria parva, the parasite causing East Coast fever (ECF) is found throughout southern Zambia. Higher values of T. parva sero-prevalence were observed in the plateau districts of Monze, Choma and Mazabuka than in the valley districts of Siavonga and Sinazongwe. Our results reveal a strong association between high T. parva sero-prevalence and the presence of the periodic climatic phenomenon known as the El Niño Southern Oscillation. More T. parva sero-positive samples were recorded during El Niño years (1997/98) (P<0.001) than other years in the study period. From this association, we conclude that Multiple El Niño Southern Oscillation Indices can be used to predict years with high or low ECF infection prevalence thereby contributing to the improved control of ECF in the area.