Surveillance of vector breeding sites and community engagement interventions in dengue control during high disease surge in the Trincomalee District, Eastern Sri Lanka

Dengue has become a significant public health concern in Sri Lanka, with the Trincomalee District consistently recording high infection rates despite its relatively sparse population. This study aimed to evaluate the abundance of dengue vectors and the community’s awareness of dengue control across 18 Grama Niladari Divisions (GNDs) in the Trincomalee town area during 2019 and 2020. Surveillance focused on the dengue vectors Aedes aegypti and Aedes albopictus by calculating the Premises Index (PI) and Container Index (CI). A questionnaire assessed community engagement in dengue control programs by evaluating Knowledge, Attitude, and Practices (KAP). Meteorological data and dengue cases were analysed using Pearson’s correlation in SPSS. Out of 6,116 premises and 19,458 containers (7,936 wet, 11,522 dry) surveyed, 526 premises and 642 containers were positive for Aedes larvae. Aedes aegypti (82.7%) was the dominant species, indicating high dengue risk. Among the GNDs, two high risk (PI> 12.8%; Aras.. and M) and seven moderately riski PI> 09.4%; A, C, L, P, ST, and U) were  identified. Water-storing items (34.4%) were the main wet containers, while discarded containers were the main dry (39.9%) container types. No significant correlation was found between rainfall and dengue cases (r = 0.198, p = 0.352), while a significant negative correlation was reported between dengue cases and temperature (r = -0.420, p = 0.041). The KAP survey revealed 82% of participants had sufficient knowledge of dengue control, 80% claimed to practice good dengue control measures, and 88% had positive attitudes towards dengue control measures. However, 68% were not eager to contribute to the community’s dengue control activities. The identification of high- and moderate-risk areas enables the recommendation of targeted interventions, such as larvicide application to potential breeding sites. The findings indicate that reliable tap water supply, proper water storage practices, and sustained community-led initiatives are essential for long-term dengue control in the region.