What Is It?

     Sleeping sickness, also known as Human African Trypanosomiasis (HAT), is caused by Trypanosoma brucei rhodensiense in Eastern Africa and Trypanosoma brucei gambiense in Western Africa. Both protozoan species are morphologically identical, but have drastically different epidemiological features. Several species of hematophagous glossina, commonly known as tsetse flies, are the vectors of these related diseases, and are responsible for cyclical transmission of the parasitic protozoan between numerous vertebrate hosts. Both forms of sleeping sickness affect the central nervous system. The term “sleeping sickness” is derived from the West African form of trypanosomiasis, primarily because invasion of the cerebrospinal fluid and brain after infection of the blood is often delayed, resulting in symptoms of extreme fatigue that can last for several years before the severe phase of the disease sets in; toxemia, coma and death. In contrast, the typical East African form of trypanosomiasis is characterized by rapid and acute development of the disease, and untreated patients can die within weeks or months of infection.