Sleeping sickness, also known as African trypanosomiasis, is caused by the parasitic flagellate Trypanosoma brucei, which is injected into the body by the tsetse fly. The disease occurs only in the 36 sub-Saharan African countries exposed to the tsetse fly. Following efforts to combat the disease, the number of cases has fallen since the 90s. Currently, although 70 million people live in high-risk areas, there are only less than a thousand new cases per year. However, the relaxation of surveillance could be accompanied by a rise in the number of cases, as observed in Guinea following the Ebola outbreak in 2013.