Viewpoints Visceral Leishmaniasis as an AIDS Defining Condition: Towards Consistency across WHO Guidelines

Given the detrimental interaction be-tween both pathogens, visceral leishman-iasis (VL)–HIV co-infection has been identified as one of the emerging chal-lenges for VL control [1]. The epidemio-logical impact of HIV on VL was most strikingly illustrated by the effect of the HIV epidemic in VL-endemic countries in southern Europe, with HIV contributing to the re-emergence of VL. By early 2000, almost 2,000 cases of VL–HIV co-infec-tion (predominantly in intravenous drug users) had been identified, with up to 50%–60 % of all VL cases being HIV co-infected [2]. Fortunately, with the wide-scale introduction of highly active antiret-roviral therapy (ART), a gradual decline in VL incidence has been observed in Europe over the last decade [1,3]. Cur-rently, the burden of VL–HIV co-infec-tion is most apparent in some regions in East Africa, like Northwest Ethiopia, where between 20%–40 % of VL cases are co-infected with HIV [1]. The prob-lem also seems to be emerging in India and Brazil [1]. There is abundant evidence that HIV strongly affects VL treatment response, including in the East African setting. Initial parasitological failure rates are typically below 2%–3 % in immunocom-petent individuals, but can be as high as 50 % in co-infected patients [4]. Case fatality rates in East Africa are 3–9-fold higher in HIV co-infected patients, reach-ing up to 15%–33 % [1,5]. Whereas relapses are uncommon (,5%) in immu-nocompetent individuals, this can reach 50%–60 % by one year in some high-risk HIV co-infected individuals [1,6]. ART is apparently only partially protective against relapse [6]. Importantly, repeated relapses tend to become increasingly unresponsive to treatment, and secondary prophylaxis is often required until sufficient CD4 cell count recovery has taken place (at least in areas with zoonotic transmission) [1]. At an early stage, several meetings on VL–HIV co-infection were organized b