Trypanososma brucei rhodesiense Sleeping Sickness, Uganda

To the Editor: The past 2 decades have heralded notable success in efforts to control sleeping sickness (human African trypanosomiasis [HAT]) in Africa. HAT is a neglected tropical disease with major public health and economic effects in sub-Saharan Africa, and its effects on livestock productivity and development are considered major constraints to alleviating poverty in this region (1,2). Because of concerted and coordinated continental control efforts, its incidence has steadily decreased. Despite these successes, concern has increased recently regarding potential convergence of the 2 causes of HAT (Trypanosoma brucei gambiense and T. brucei rhodesiense). These organisms differ in transmission and how infections are diagnosed and treated, and control, and have never coincided in the same area. Uganda is the only country with endemic distributions of these 2 trypanosome species, and convergence there represents a major public health concern, given the potential for overlapping infections to compromise treatment and control programs and spread into neighboring countries (3,4). Risk for convergence led to an international emergency intervention. In 2006, an international public– private partnership, Stamp Out Sleeping Sickness (SOS), was established to control spread of this disease in central Uganda (5). However, despite the continental effect of convergence of the 2 causes of HAT, little is known about trends in incidence and epidemiology of HAT in central Uganda. We report results of data analysis for HAT caused by T. b. rhodesiense during 2000–2009. This study was approved by the ethics review board for human subjects at McGill University (Montreal. Quebec, Canada). We obtained data on case-patients given a diagnosis of T. b. rhodesiense HAT at a HAT treatment unit in Uganda. These diagnoses were reported to the National Sleeping Sickness Control Program of the Ministry of Health (4,6). Data were assigned locations by parish, and analyses focused on spatiotemporal trends in case occurrence. The fi nal cleaned dataset contained 2,501 reported cases of presumed T. b. rhodesiense HAT. In the past 10 years in Uganda, 140 cases of fatal T. b. rhodesiense HAT have been reported. However, given estimates of underreporting and cessation of active surveillance, actual deaths are likely > 1,700 (170 deaths/ year) (6). Notably, mortality rates have increased from an average of 5% in the early 2000s to ≈10% in later years, and rates have been higher in recently affected districts. This pattern is predominantly driven by higher mortality rates in newly affected SOS districts in central Uganda, in …