Video. Lesson on African Trypanosomiasis (African Sleeping Sickness): Causes, Symptoms and Treatment. African Trypanosomiasis is caused by parasitic protozoa from the genus trypanosoma. Trypanosoma protozoa are carried in the tsetse fly, and when a person is bitten by a tsetse fly, trypomastigotes enter the bloodstream of the infected individual. Trypomastigotes also enter lymphatic system and spinal fluid, where they multiply by binary fission. Systems affected in African Trypanosomiasis include the skin, lymphatic system and central nervous system.