Trypanosomosis (Animal)
Primary reference(s)
FAO, 2020. Programme Against African Trypanosomosis (PAAT). Food and Agriculture Organization of the United Nations (FAO). Accessed 26 October 2020.
Additional scientific description
Tsetse-transmitted animal trypanosomosis occurs in tropical regions of sub-Saharan Africa, where it constitutes a major obstacle to the development of animal production. The considerable economic and social repercussions make control of this disease a priority for the development of a large part of the African continent. African animal trypanosomosis affects ruminants, swine, camels, equines, carnivores, as well as a broad range of wild animals, but the heaviest economic burden is in cattle. In cattle, the disease is called Nagana. The disease is caused by several species of trypanosome but mainly by Trypanosoma congolense, T. vivax, T. brucei, and T. simiae. T. vivax is also present is Latin America, where in the absence of tsetse flies it is transmitted by other biting flies. It is known as American trypanosomiasis or Chagas disease. A different species (i.e., T. evansi) is also present outside of Africa, including Asia. Control and elimination of animal trypanosomosis as a zoonotic disease would help to improve animal production in Africa considerably and would also contribute to enhance human health (WHO, 2020).
Transmission of trypanosomes by insects occurs through cyclical transmission or mechanical transmission. Cyclical transmission, during which the trypanosomes actively multiply in the vectors, occurs through the intermediary of tsetse flies (Glossina spp.). Mechanical transmission can be caused by various blood-sucking insects such as flies of the family Tabanidae (horse flies) and Stomoxys spp. (FAO, 1983).
Trypanosoma brucei, and in particular the two subspecies T. brucei gambiense and T. brucei rhodesiense are the causes of human African trypanosomosis, also known as sleeping sickness. Animals can host the human pathogen parasites, especially T. brucei rhodesiense, of which domestic and wild animals are the most important reservoir. Animals can also be infected with T. brucei gambiense and probably act as a reservoir to a lesser extent. However, the precise epidemiological role of the animal reservoir in the gambiense form of the disease is not yet well known (WHO, 2020).
Metrics and numeric limits
Not identified.
Key relevant UN convention / multilateral treaty
WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement) (WTO, 1994).
Examples of drivers, outcomes and risk management
Trypanosomosis (tsetse-transmitted) is one of the World Organisation for Animal Health (OIE) Listed diseases, infections and infestations in force in 2020 (OIE, 2020).
Drivers: presence/introduction of Trypanosoma infected tsetse fly.
Outcomes: mortality and morbidity of animals and humans, spread of infection.
Risk management: treatment with trypanocide, vector control program, animal movement control, improved biosecurity.
References
FAO, 1983. FAO Animal Production and Health Paper 37. African animal trypanosomiasis selected articles from the World Animal Review (1983). Food and Agriculture Organization of the United Nations (FAO). Accessed 26 October 2020.
OIE, 2020. OIE-Listed diseases, infections and infestations in force in 2020. World Organisation for Animal Health (OIE). Accessed 27 October 2020.
WHO, 2020. Trypanosomiasis, human African (sleeping sickness). World Health Organization (WHO). Accessed 26 October 2020.
WTO, 1994. The WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement). World Trade Organization (WTO). Accessed 3 October 2020.