Systematic survey and spatial mapping of discarded tyres as breeding habitats of Aedes spp

Discarded tyres collect rainwater, facilitating the breeding of Aedes spp. mosquitoes and increasing dengue transmission risk. However, there remains a gap in understanding the factors influencing Aedes spp. distribution along transport networks in the sub-Himalayan region of West Bengal. To address this, an entomological survey was conducted on discarded tyres along a 200-km-long transport corridor, covering 34 sites. Each tyre was examined for Aedes spp. larvae. Collected larvae were reared to adults for morphological identification. Tyres were categorized by type, distance from human settlements, shade conditions, water volume and organic matter content. Larval positivity, density, and species distribution were analyzed and spatial clustering of hotspots was mapped using Kernel density estimation (KDE) in QGIS. Of the 1104 tyres inspected, 605 (54.8%) were positive for larvae. Aedes aegypti mostly exhibited higher larval density than Aedes albopictus. While tyre positivity was significantly higher near human settlements, larval density did not vary with distance. Shade and water volume did not affect tyre positivity; however, larval density was positively associated with water volume and tyre size. The presence of organic matter significantly increased larval positivity and favored Ae. albopictus. KDE identified distinct hotspots, indicating areas of potentially elevated dengue transmission risk, although entomological indices do not directly measure transmission. These findings suggest that discarded tyres constitute persistent and spatially clustered breeding habitats in the region of study. Consequently, motor garages should be prioritized for vector surveillance. Source-reduction measures such as safe tyre disposal, covering, or puncturing tyres to prevent water accumulation must be emphasized to strengthen dengue prevention.