Migration and the risk of animal trypanosomiasis on the Jos Plateau, Nigeria

Abstract

Until recently, the Jos Plateau in north central Nigeria was considered free of tsetse flies, vectors of human and animal trypanosomiasis in Africa. This disease severely limits livestock production in a large part of Africa but was of little relevance on the Plateau. Recent studies, however, show animal trypanosomiasis to be increasingly prevalent, leading to significant agricultural losses. Seasonal migration by Fulani pastoralists and their cattle is one of the reasons suggested for this increase. Once limited to the dry season (November-March), migration is now practiced during the wet season (April-October) as access to grazing and water is limited by expanding crop production on the Plateau. To improve our understanding of the epidemiology of the disease and design effective interventions, it is important to determine the risk that this practice poses to livestock on the Plateau. In this work, a migrant herd was followed from June 2013 to February 2014. Captured tsetse flies and cattle blood samples were screened for trypanosomes using ITS-1 PCR. Results show that cattle infection was almost zero between June and September but rose to 16.7% (12/72, 95%CI 9.8-26.9%) by the end of November. The infection rate in tsetse was 21.3% (17/80, 95%CI 13.7-31.4%) with Trypanosoma vivax the predominant species in both cattle and flies. We conclude that animals moving through this route to the base of the Plateau are subject to a higher trypanosomiasis challenge than on the Plateau and may bring these infections back to the Plateau when they return.