Phase contrast micrograph of Trypanosoma gambiense, the cause of sleeping sickness, in the bloodstream of a rat. T. gambiense organisms are the long thin curved cells (blue). T. gambiense is a parasitic protozoa that is the causative agent of African sleeping sickness called trypanosome. This protozoa is transmitted to humans through the bite of Tse-tse fly. Once introduced by an infected fly, the trypanosomes proliferate and invade all the organs of the host. Without treatment, the parasite will invade the central nervous system. When the nervous system has been attacked, the patient's behavior will change. they will become indifferent to their environment, and be exhausted by periods of sleep-like unconsciousness. Finally, patients fall into a coma and die. 250x at 35mm size.