Overview of the Vectors and Their Role in Transmission of African Animal Trypanosomiasis

African animal trypanosomiasis (AAT) is a major constraint to livestock productivity, particularly in cattle and in camels. This chapter covers some general aspects of the arthropod vectors of animal trypanosomiasis, the tsetse flies Glossina spp., and to a lesser extent the biting flies. This chapter covers the classification, morphology, basic biology, and the eco-distribution of tsetse flies. The role of tsetse flies in disease epidemiology has also been reviewed. The elementary biology of these vectors is quite well known and elucidated. However, with advances in molecular and other biological techniques, new insights related to tsetse biology have been obtained. This chapter will revisit these basics and include some updated information emanating from research done in the recent past. The final part of the chapter is devoted to a brief discussion on biting flies, the vectors of T. evansi, which causes camel trypanosomiasis.

Epidemiology and Economic Importance of African Animal Trypanosomiasis

African animal trypanosomiasis (AAT), also called Nagana, is a vector-borne parasitic disease caused by an extracellular protozoan belonging to the genus Trypanosoma. It has serious effects on the health status and welfare of domestic mammals which considerably results in a reduction in their productivity. In this review, a comprehensive overview of the epidemiology of AAT was provided with a special focus on its general clinical aspects (the clinical signs and pathogenesis as well as its transmission cycle), the parasite (Trypanosoma spp.), the parasite life cycle and transmission, its vector (Glossina spp.), tsetse fly lifecycle and reproduction, risk factors of AAT, and economic importance of AAT in the affected countries. The present work gave a detailed account of epidemiology in the context of infestation patterns, the parasite causing it, its vector, and the economic impacts of the disease on different livestock species.

Role of Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC) in Control of African Animal Trypanosomiasis (AAT)/Nagana

The role of the Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC) in the control of animal trypanosomiasis is premised on the fact that a large proportion of animal trypanosomiasis in Kenya is tsetse transmitted. Tsetse distribution in Kenya is characterized by eight discontinuous belts defined by topographical, environmental and land-use. KENTTEC's strategy for control of African animal trypanosomiasis is based on use of community-based organizations for spraying of livestock, control of the vector using various devices such as targets and traps, and development of strategies and policies for use of land after the intervention. The council has developed linkage with research institutions for adaptive and operational research. The council has initiated the development of national atlas by mapping tsetse and animal trypanosomiasis distribution in collaboration with stakeholders at the national, regional, and international levels.

Design of an Epitope-Based Vaccine Ensemble for Animal Trypanosomiasis by Computational Methods

African animal trypanosomiasis is caused by vector-transmitted parasites of the genus Trypanosoma. T. congolense and T. brucei brucei are predominant in Africa; T. evansi and T. vivax in America and Asia. They have in common an extracellular lifestyle and livestock tropism, which provokes huge economic losses in regions where vectors are endemic. There are licensed drugs to treat the infections, but adherence to treatment is poor and appearance of resistances common. Therefore, the availability of a prophylactic vaccine would represent a major breakthrough towards the management and control of the disease. Selection of the most appropriate antigens for its development is a bottleneck step, especially considering the limited resources allocated. Herein we propose a vaccine strategy based on multiple epitopes from multiple antigens to counteract the parasites´ biological complexity. Epitopes were identified by computer-assisted genome-wide screenings, considering sequence conservation criteria, antigens annotation and sub-cellular localization, high binding affinity to antigen presenting molecules, and lack of cross-reactivity to proteins in cattle and other breeding species. We ultimately provide 31 B-cell, 8 CD4 T-cell, and 15 CD8 T-cell epitope sequences from 30 distinct antigens for the prospective design of a genetic ensemble vaccine against the four trypanosome species responsible for African animal trypanosomiasis.