African Trypanosomiasis, also known as "sleeping sickness," is caused by microscopic parasites of the species Trypanosoma brucei. It is transmitted by the tsetse fly (Glossina species), which is found only in rural Africa. Although the infection is not found in the United States, historically, it has been a serious public health problem in some regions of sub-Saharan Africa. Currently, about 10,000 new cases each year are reported to the World Health organization; however, it is believed that many cases go undiagnosed and unreported. Sleeping sickness is curable with medication, but is fatal if left untreated.