Update on human African trypanosomiasis (sleeping sickness).

Human African trypanosomiasis (HAT), also known as sleeping sickness, is one of the Africa's 'neglected diseases' and is caused by infection with protozoan parasites of the Trypanosoma genus. Transmitted by the bite of the tsetse fly, it puts 70 million people at risk throughout sub-Saharan Africa and is usually fatal if untreated or inadequately treated. In this brief overview, some important recent developments in this disease are outlined. These cover various aspects including a reduction in disease incidence, newly recognised parasite reservoir sites in humans, disease outcome, novel diagnostic methods, new and improved treatment, and disease neuropathogenesis.