Silent Vectors: The Spread of Leishmaniasis Across the Indian Subcontinent and into the Himalayas

Abstract

Leishmaniasis, a neglected tropical disease caused by protozoan parasites of the genus Leishmania and transmitted by phlebotomine sandflies, is undergoing a notable shift in its epidemiological distribution (World Health Organization [WHO], 2023; Burza et al., 2018). Traditionally restricted to lowland endemic regions of the Indian subcontinent, the disease is increasingly reported in higher altitudes, particularly in the Himalayan region. This transition is driven by climate change, environmental modifications, and human migration, which collectively enhance vector survival and transmission potential in previously unsuitable regions (Purse et al., 2017; González et al., 2010). The disease’s diverse clinical manifestations complicate diagnosis in resource-limited settings, while socioeconomic vulnerabilities exacerbate its burden (Oryan & Akbari, 2016). Current control strategies face limitations due to vector adaptation, insecticide resistance, and logistical constraints. This study elucidates the interplay of climatic, ecological, and anthropogenic factors contributing to this shift and highlights the urgent need for integrated, region-specific public health interventions.