Entomological Assessment of the Risk of Dengue Epidemic in the Lawspet Constituency, Puducherry

Vector-borne diseases (VBDs) account for 17% of the global infectious disease burden, causing 7,00,000 deaths annually. Dengue fever remains a public health concern in India, with 32,091 cases and 32 deaths reported by June 30, 2024. Lawspet constituency in Puducherry, a dengue hotspot, provides ideal conditions for Aedes mosquito breeding. Dengue source reduction, a cost-effective strategy, targets breeding sites to interrupt the mosquito life-cycle. This study aims to assess Aedes immature positivity through a door-to-door survey in 464 households of Pedhuchettipet ward, Lawspet constituency.

A door-to-door Aedes survey was conducted in the ward Pedhuchettipet from April to May 2024. Of 960 households, 464 (48.3%) were surveyed following WHO entomological protocols. Various water-holding containers were inspected. Collected Aedes immatures were reared under controlled conditions (27°C ± 2°C, RH 70 ± 2%) until adult emergence and the adults were identified using taxonomic keys. House index (HI), Breteau index (BI), and Container index (CI) were calculated to assess dengue risk in the study area. Data were analyzed using Microsoft Excel program.

Among 464 houses, 17 (3.6%) had Aedes immatures, with 24 positive containers. 200 immatures emerged and all identified as Aedes aegypti with a 60% emergence rate. HI (3.6%), BI (5.17%), and CI (4.36%) exceeded the dengue transmission threshold, highlighting the risk level.

Findings indicate moderate dengue transmission risk, stressing the need for continuous surveillance and vector control. Source reduction, community interventions, and biological control are crucial in mitigating dengue risks. Environmental management and public awareness can reduce Aedes populations, lowering dengue outbreak risks in the area.