It is known as the sleeping sickness in humans and nagana in animals. Transmission of this parasite between mammal host is usually by an insect vector, the tsetse fly. When contacting from fly to human, the parasite undergoes a morphological change. It’s one of the few pathogens in the world that can cross the blood-brain barrier found in the central nervous system. The sleeping sickness name reference the fact that when a disease reach 2nd stage, it brings confusion, poor coordination, numbness and having a difficulty in sleeping.