Mapping landscape changes to address dengue fever risk in Laos and Thailand

Abstract

Land use and land cover (LULC) are changing rapidly worldwide, with climate change making living conditions uncomfortable for humans while creating favorable environments for dengue vectors, Aedes aegypti and Aedes albopictus. Laos and Thailand are endemic to dengue, with frequent outbreaks reported. Cleared forests allow vectors to interact with nearby human hosts, potentially transferring viruses from zoonotic reservoirs. Urban areas are often built at the expense of natural hydrology, forests, or farmland. These areas, known as urban heat islands, absorb heat because of construction materials that retain warmth. This, along with water containers or paddles, creates ideal breeding grounds for dengue vectors. Additionally, rubber plantations have been identified as breeding sites for vectors, which can worsen endemic conditions. This study aimed to map LULC changes associated with dengue vector proliferation from 2001 to 2025 using Landsat satellite images (1 to 8). Random Forests classification, a supervised machine learning method, was used to delineate LULC patterns. Satellite-derived LULC data showed a significant decrease in forest cover, an increase in settlements, and a shift in agricultural crops from food crops to cash crops, specifically rubber, confirming changes previously linked to dengue vector ecology. These findings raise serious concerns for public health agencies in both countries and provide valuable insights for cross-sectoral policies in public health, urban planning, forestry, and agriculture sectors.