Visceral Leishmaniasis-HIV coinfection as a predictor of increased leishmania transmission at the village level in Bihar, India

Abstract

Background: Visceral leishmaniasis (VL) is on the verge of being eliminated as a public health problem in the Indian subcontinent. Although Post kala azar dermal leishmaniasis (PKDL) is recognized as an important reservoir of transmission, we hypothesized that patients with VL coinfected with Human Immunodeficiency Virus (HIV) may also be important reservoirs of sustained leishmania transmission. We therefore investigated to what extent cases of PKDL or VL−HIV are associated with VL incidence at the village level in Bihar, India. Methods: VL, VL−HIV, and PKDL case data from six districts within the highly VL endemic state of Bihar, India were collected through the Kala Azar Management Information System for the years 2014−2019. Multivariate analysis was done using negative binomial regression controlling for year as a fixed effect and block (subdistrict) as a random effect. Findings: Presence of VL−HIV and PKDL cases were both associated with a more than twofold increase in VL incidence at village level, with Incidence Rate Ratios (IRR) of 2.16 (95% CI 1.81−2.58) and 2.37 (95% CI 2.01−2.81) for VL−HIV and PKDL cases respectively. A sensitivity analysis showed the strength of the association to be similar in each of the six included subdistricts. Conclusions: These findings indicate the importance of VL−HIV patients as infectious reservoirs, and suggest that they represent a threat equivalent to PKDL patients towards the VL elimination initiative on the Indian subcontinent, therefore warranting a similar focus.