The areas occupied by the tsetse fly were largely barred to animal husbandry. Trypanosomiasis could, in future be prevented by genetically altering the tsetse fly. Wild mammal populations increased rapidly, accompanied by the tsetse fly. Infection occurs when a vector tsetse fly bites a mammalian host. Human African trypanosomiasis is vector-borne, and spread through the bite of the tsetse fly. Concerning health, 53% of the zone is exposed to malaria and none to Tsetse fly. Occasionally, a red sore will develop at the location of the tsetse fly bite. Studies of the tsetse fly show that females generally mate only once (occasionally twice). "T. brucei" is found where the tsetse fly vectors are prevalent. One conventional argument is that the Tsetse fly made it difficult to use draught animals. The insect vectors for "T. brucei" are different species of tsetse fly (genus "Glossina"). Sometimes, wild animals can be infected by the tsetse fly and they act as reservoirs. It is transmitted by the tsetse fly and is found almost exclusively in Sub-Saharan Africa. The tsetse fly vector ranges mostly in the central part of Africa. The short and stumpy trypomastigotes are taken up by tsetse fly during blood meal.