Visceral Leishmaniasis in Sub-Himalayan India (1967-2023): A Systematic Review.

Substantial gains have been achieved in the control of visceral leishmaniasis (VL) in the four endemic states of India; however, cases are sporadically reported from other nonendemic regions of India such as the sub-Himalayan region, which can be a hurdle to VL elimination. We analyzed VL reports published from the sub-Himalayan regions of India over seven decades (1967-2023) in this systematic review. Medline, Embase, Scopus, and Web of Science were searched for VL cases from sub-Himalayan regions of India. The demographic data, clinical presentation, diagnostic modality, treatment, outcomes of the cases, and overall year-wise and geographical distribution of the cases were analyzed; studies on the sand fly vector were also included. From 535 articles, 33 studies were included in the analysis. Overall, 228 patients were diagnosed with VL in the sub-Himalayan region of India from 1967 to 2023. These cases were reported from Uttarakhand (n = 178), Himachal Pradesh (n = 39), and Jammu and Kashmir (n = 11). Most patients (88.4%) did not have a history of travel outside their native places. Three pediatric cases were reported from Jammu and Kashmir. The DNA of Leishmania donovani was detected in four of the 52 (7.7%) sand flies collected from Himachal Pradesh. The published literature points toward the existence of local transmission of VL in the sub-Himalayan region of India, strongly substantiated by the emergence of pediatric VL in some places. Thus, these difficult-to-reach hilly states of India will require focused surveillance for VL to successfully achieve elimination goals.