Seasonal variation of Aedes population in Bidhannagar Municipal Corporation areas, West Bengal, India

Dengue has emerged as a major global public health concern, particularly with increased incidence in urban and semi-urban areas. During last 5 years, a significant number of dengue cases were reported from the urban areas of West Bengal including Bidhannagar Municipal Corporation. Prevention and control of dengue mainly depends on reduction of vector populations as no specific treatment is available till date. Information regarding vector abundance and population dynamics is essential for formulation of effective control strategies. So, the present study was undertaken to study the seasonal variation of dengue vector population in Bidhannagar Municipal Corporation, Kolkata, West Bengal. The present study was conducted during May 2022 and April 2023. Eentomological collections were conducted on monthly basis to examine potential breeding sites for immature stages of Aedes sp. Survey data were used for calculation of breeding preference ratio (BPR), House Index (HI), Container Index (CI) and Breteau Index (BI) and its associations with environmental factors were also analyzed. During study, 3830 houses and 14,565 water-holding containers were inspected. Highest house and container positivity were recorded during monsoon, with peak between August and September. Highest BPR was recorded in case of clay pot (1.7–2.0), ceramic container (0.9–2.0), and metallic pot (1.3–2.0). Entomological indices such as HI (0–41.67), CI (0–10.27) and BI (0–79.67) showed significant seasonal variation. Overall, highest HI (41.67) and CI (10.27) were recorded in September, whereas August registered the top BI value at 79.67. The association of rainfall, humidity, and minimum temperature with vector indices was stronger than that of average temperature. Maximum temperature had a relatively weak yet statistically significant positive correlation with the BI. The study findings may serve as a base line data for developing predictive models and focused interventions. Future research should continue to explore the interactions between Aedes vectors and environmental variables to refine strategies for dengue prevention and control.