Utility of microstratification to identify hotspots for visceral leishmaniasis in Nepal.

Micro-stratification in the context of visceral leishmaniasis (VL) was done for the first time in Nepal. Public health interventions and resources can be targeted to the specific needs of each stratum. The micro-stratification of VL risk was carried out to identify VL risk wards (smallest administrative unit) in the country. Ward wise number of VL cases for six years (2017-2022) were obtained from the Epidemiology and Disease Control Division to determine ward wise incidence of VL per 10,000 population. VL infection risk was assessed using receptivity measured through sandfly vector presence data, temperature, altitude, housing conditions, and vulnerability measured through migration data of the district. Among 6743 wards of 77 districts, there were 58 wards in 2017, 68 in 2018, 69 in 2019, 52 in 2020, 82 in 2021, and 84 in 2022 at high risk of VL. The number of high risk wards is increasing since 2020 and most of them are located in Karnali and Sudurpaschim provinces. We recommend strengthening health care facilities in high and moderate risk areas for early diagnosis and prompt case management, implementing active surveillance to respond to any VL cases, to prioritize and intensify indoor residual spraying for vector control, and conduct health education campaigns to increase VL awareness.