Impact of rainfall on East Coast Fever in cattle at Ol Pejeta Conservancy, Kenya

Abstract: Weather conditions commonly have a large impact on tick-borne diseases as it affects the abundance of the tick vector. The cattle disease East Coast Fever (ECF) is no exception. Rainfall particularly seems to play an important role in the transmission of ECF. In this study I examined the associations between precipitation and cattle mortality due to ECF in Ol Pejeta Conservancy in Laikipia, Kenya. Long-term data on daily ECF mortality during the years 2016-2021 was compared with rainfall during this same period. The results showed that ECF-related deaths follow rainfall with a peak lag effect on 21 days. The results suggest that control measures for reduction of ticks need to be increased during rainy periods and can possibly be decreased during periods of drought. The close interaction between oxpeckers and large herbivores has been known for many years. The birds feed on ticks and other ectoparasites from their host animal. Whether the cleaning interactions between oxpeckers and cattle could be a good indicator of tick-load on the cattle was analyzed in this study. The intention was to investigate whether the quantity of oxpeckers could be used as a simple measurement for when treatment with acaricides is needed. Due to lack of oxpeckers in the observations performed it was not possible to detect a correlation between tick-load and number of oxpeckers on cattle in this study. The results point towards oxpeckers not being a good measurement of tick-load on cattle treated with acaricides.