Sleeping sickness, also known as African trypanosomiasis, is a tropical disease caused by the parasite Trypanosoma. It is transmitted to humans through the bite of infected tsetse flies. The disease affects the central nervous system and can lead to confusion, behavioral changes, and eventually, coma and death if left untreated. Sleeping sickness is prevalent in sub-Saharan Africa and is considered a neglected tropical disease by the World Health Organization.