The livelihoods of millions of people living in Africa are at risk due to infectious diseases that affect the health of livestock animals that provide them with essential food, milk, clothing and draught power. One major livestock disease is animal African trypanosomiasis (AAT) which is caused by blood-dwelling Trypanosome parasites that affect many important farm animals including cattle, goats, sheep, horses and pigs.
AAT is endemic from the Southern edge of the Sahara to Zimbabwe/Mozambique and is estimated to cause annual productivity losses of over $1bn, representing a major barrier for the socioeconomic advancement of many African countries. Such is the impact of this disease that the United Nations Food and Agricultural Organisation consider it to “lie at the heart of Africa’s struggle against poverty”.
The disease is mainly caused by two species of Trypanosome: T. congolense and T. vivax which are primarily transmitted through the bite of an infected tsetse fly. One approach for managing the disease would be the deployment of an effective vaccine; however, vaccinating against trypanosome infections has long been considered unachievable because the surface of these parasites is immunologically protected by a highly abundant protein that is constantly changing within the population.
Using the genome sequence to identify non-variant parasite cell surface proteins, we have produced a library of parasite proteins and systematically tested their candidature as vaccine candidates using a murine infection model. I will present our recent results which indicate that it is possible to identify non-variant parasite proteins that can elicit protective immune responses, suggesting that a vaccine to treat AAT may be achievable.