Human African Trypanosomiasis in the Kafue National Park, Zambia

Human African Trypanosomiasis (HAT) is a neglected tropical disease [1] caused by Trypanosoma brucei rhodesiense (eastern and southern Africa) or Trypanosoma brucei gambiense (western and central Africa) and is transmitted through the bite of an infected tsetse fly (Glossina species) [2,3]. The tsetse flies acquire their infections from humans or animals harbouring the human pathogenic parasites [2]. The disease is endemic in tropical and subtropical Africa [4], where it affects low-income populations [3]. Whereas T. b. rhodesiense causes acute HAT [5,6], T. b. gambiense causes a more chronic form of the disease [5]. Although HAT has been re-emerging in most of the old foci within sub-Saharan Africa since the 1970s, with T. b. gambiense accounting for more than 98% of the reported cases [7], the latest World Health Organization (WHO) reports suggest that the number of new cases have been reduced [1]. In the year 2009, after continued control efforts, the number of cases of HAT reported dropped below 10,000 (9,878) for the first time in 50 years. This decline in number of cases has continued with 6,314 new cases reported in 2012 [1]. However, the estimated number of actual cases is about 20,000 and the estimated population at risk is 65 million people. Despite such progress, only a fraction of the population at risk for contracting HAT in sub-Saharan Africa is under surveillance and relatively few cases are diagnosed annually [8,9]. In particular, there is considerable underdiagnosis of rhodesiense HAT in sub-Saharan Africa, including Zambia, mainly due to lack of HAT surveillance and control programmes [10,11]. Historically, epidemics of rhodesiense HAT were reported from the northern and southern regions of the Luangwa Valley and the Kafue River Valley in the 1960s and early 1970s [12]. According to WHO [1], Zambia currently reports