The failure of the Church Missionary Society (CMS) to implement the use of ox-carts in place of human porters in East Africa in 1876-78 is conventionally attributed to their misunderstanding of African peoples, environment, and diseases. This article contends that there were further factors, specific to the years of their attempt, that undermined the missionaries’ designs. These were, firstly, that heightened levels of rainfall, associated with an El Niño Southern Oscillation (ENSO) event alongside a positive Indian Ocean Dipole (IOD), expanded tsetse habitats and contributed to an epidemic of trypanosomiasis; and secondly, that the murder of CMS personnel on the southeastern shores of Lake Victoria necessitated the leader of the ox-cart experiment abandoning any designs on future attempts. There is evidence to suggest that missionaries could have implemented travel by ox-cart if they had made attempts at almost any time in the nineteenth century other than in 1876-78.
Keywords: Trypanosomiasis, Climate, Rainfall, Tsetse Flies, East African History