Environmental Drivers and Spatial Distribution of Dengue Fever in Gandaki Province: Evidence From 2021 to 2024.

Background: Dengue fever, a rapidly expanding mosquito-borne disease influenced by environmental and climatic factors, has increasingly affected Nepal's Gandaki Province, prompting this study to investigate its spatial distribution and drivers from 2021 to 2024.

Methods: This study analysed the spatial distribution of dengue incidence in Gandaki Province, Nepal, from 2021 to 2024 by integrating environmental variables such as temperature, precipitation, vegetation, and water indices using remote sensing datasets. Spatial autocorrelation and cluster patterns were assessed through Global and Local Moran's I and Local Indicators of Spatial Association using QGIS and GeoDa software.

Results: From 2021 to 2024, the incidence of dengue in Gandaki Province surged from 4.56 to 431 cases per 100,000 population. Spatial autocorrelation analysis showed weak negative clustering from 2021 to 2023 (Moran's I = -0.016, -0.056, -0.031, respectively), followed by the emergence of weak positive clustering in 2024 (Moran's I = 0.049). Local spatial analysis identified dengue hotspots in Devghat, Bandipur and Pokhara. Over time, environmental variables such as Normalised Difference Vegetation Index, Normalised Difference Water Index, Land Surface Temperature, precipitation and Leaf Area Index showed stronger positive correlations with dengue, highlighting the growing influence of climate on transmission patterns.

Conclusions: This study highlights the increasing influence of environmental and climatic factors on dengue transmission in Gandaki Province. Spatial analysis identified key hotspots and revealed shifting correlations between dengue incidence and variables such as temperature, vegetation and precipitation. These findings underscore the need for integrated surveillance and early warning systems that incorporate environmental data to enhance dengue prevention and control strategies in the region.