African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species Trypanosoma brucei. Humans are infected by two types, Trypanosoma brucei gambiense (TbG) and Trypanosoma brucei rhodesiense (TbR). TbG causes over 98% of reported cases. Both are usually transmitted by the bite of an infected tsetse fly and are most common in rural areas.Initially, the first stage of the disease is characterized by fevers, headaches, itchiness, and joint pains, beginning one to three weeks after the bite. Weeks to months later, the second stage begins with confusion, poor coordination, numbness, and trouble sleeping. Diagnosis is by finding the parasite in a blood smear or in the fluid of a lymph node. A lumbar puncture is often needed to tell the difference between first- and second-stage disease. If the disease is not treated quickly it can lead to death. Prevention of severe disease involves screening the at-risk population with blood tests for TbG. Treatment is easier when the disease is detected early and before neurological symptoms occur. Treatment of the first stage has been with the medications pentamidine or suramin. Treatment of the second stage has involved eflornithine or a combination of nifurtimox and eflornithine for TbG. Fexinidazole is a more recent treatment that can be taken by mouth, for either  stages of TbG. While melarsoprol works for both types, it is typically only used for TbR, due to serious side effects.
In 2001, Aventis, in association with Médecins Sans Frontières and the World Health Organization, signed a long-term agreement to manufacture and donate the drug.In addition to sleeping sickness, previous names have included negro lethargy, maladie du sommeil (Fr), Schlafkrankheit (Ger), African lethargy, and Congo trypanosomiasis. The British-led Sleeping Sickness Commission collecting tsetse flies, Uganda and Nyasaland, 1908-1913

Research
The genome of the parasite has been sequenced and several proteins have been identified as potential targets for drug treatment. Analysis of the genome also revealed the reason why generating a vaccine for this disease has been so difficult. T. brucei has over 800 genes that make proteins the parasite "mixes and matches" to evade immune system detection.Using a genetically modified form of a bacterium that occurs naturally in the gut of the vectors is being studied as a method of controlling the disease.Recent findings indicate that the parasite is unable to survive in the bloodstream without its flagellum. This insight gives researchers a new angle with which to attack the parasite.Trypanosomiasis vaccines are undergoing research. Additionally, the Drugs for Neglected Diseases Initiative has contributed to the African sleeping sickness research by developing a compound called fexinidazole. This project was originally started in April 2007 and enrolled 749 people in the DRC and Central African Republic. The results showed efficacy and safety in both stages of the disease, both in adults and children ≥ 6 years old and weighing ≥ 20 kg. The European Medicines Agency approved it for first and second stage disease outside of Europe in November 2018.