Diversity of human African trypanosomiasis epidemiological settings requires fine-tuning control strategies to facilitate disease elimination

Abstract

In 2001, the World Health Organization (WHO) established a public–private partnership to fight human African trypanosomiasis (HAT). As a result of this continuous collaboration, and in addition to the coordination with nongovernmental organizations and bilateral cooperation agencies, the number of new cases of HAT annually reported by the WHO has strikingly decreased. In 2012, HAT was included in WHO's roadmap on neglected tropical diseases with a 2020 target date for elimination. Although the prevalence of HAT is decreasing and its elimination is targeted, control approaches must be adapted to the differ-ent epidemiological patterns in order to adopt the most adequate strategies to maintain their cost-effectiveness. These strategies must be flexible and dynamic in order to be adapted to the disease progression, as well as to the changes affecting the existing health facilities in transmission areas, including their accessibility, their capabilities, and their involvement in the elimination process. Considering the different patterns of transmission (Trypanosoma brucei (T.b.) rhodesiense HAT) and transmission intensity (T.b. gambiense HAT), differ-ent settings have been defined. In the case of T.b. rhodesiense, this form exists primarily where wild animals are the main parasite reservoir, and where the main parasite reservoir is cattle. In T.b. gambiense, this form exists in areas with high intensity transmission, areas with moderate intensity transmission, and areas with low intensity transmission. Criteria and indicators must be established to monitor and evaluate the actions implemented toward the elimination of HAT.