The Impact of Trypanosomiasis on Ethiopian Livestock

This study examines the impact of trypanosomiasis on the livestock industry of Ethiopia and discusses the need for further research, diagnosis and control in the future. The thesis begins with a brief introduction to the country's geographical location and it's livestock industry. The institutions involved in research and extension to improve the livestock sector and supported by the government and non-governmental organisations are described. The first chapter is a review of the epidemiology of trypanosomiasis in Ethiopia (past and present). This includes the distribution of tsetse-flies, their progress to higher altitudes, the ecological factors involved in the tsetse advance and the role of tsetse as vectors of trypanosomes. Tsetse and non-tsetse transmitted trypanosomiasis and their occurrence in relation to the tsetse distribution and the prevalence of trypanosomiasis in domestic livestock and humans are discussed. The main emphasis of the third chapter is an assessment of the socioeconomic impact of trypanosomiasis in Ethiopia. This involves livestock production systems, the importance of livestock in the Ethiopian economy and the interaction between livestock and crop production particularly in the highlands and investigates the reasons why livestock production is precluded from most of the lowland areas of the country. In order to quantify the direct economic losses due to trypanosomiasis in the tsetse-infested areas of Ethiopia assumptions are made on the number of livestock at risk, the prevalence of the disease, mortality rate for different species of domestic livestock and the prices of livestock and livestock products based on previous studies and current prices in Ethiopia and neighbouring countries. The direct production losses, through mortality, morbidity and infertility account for about 97% of the total and research, investigation and control costs incurred by the National Tsetse and Trypanosomiasis Investigation and Control Centre (NTTICC) accounts for 3% of the total direct cost. It is recognised that indirect losses caused by the disease in preventing or impairing agricultural development are far greater than the direct losses. However indirect losses are very difficult to quantify because the development of the tsetse-infested areas requires an integrated lowland development scheme. This chapter takes account of the seriousness of the problem and assesses different control methods and future control options. The third chapter provides a review of Trypanosoma equiperdum in equines. The historical background of the disease, it's distribution, morphology, transmission, clinical signs, pathogenesis, diagnosis, immunity and control measures are discussed. The fourth chapter presents results of a survey of horses in the Arsi and Bale regions of Ethiopia using ELISAs to detect antibodies to, and antigens of T equiperdum. The study was focused on seven selected sites and 309 horses of both sexes were clinically examined and blood sampled. Testing of the sera was initially carried out in Ethiopia. Later all 309 sera were retested in Glasgow to confirm the results. Blood and genital washes from seven antigenaemic horses (5 female and 2 male) were inoculated into laboratory rodents in an attempt to isolate the parasites but none developed a patent parasitaemia. The ELISA results showed that 101 horses had high antibody positivity, whilst only 19 horses gave high antigen positivity when compared with strong positive controls. The results obtained from the antibody and antigen ELISAs were analysed and correlated with the clinical signs (p<0.001 and p