Industrial hotspot: Infestation of invasive Aedes aegypti and Aedes albopictus in Puducherry, India.

Abstract

Objectives: Industrial zones are large, unsupervised areas with a high risk of Aedes vector infestation because of the presence of diverse artificial breeding habitats. Unlike community-based Aedes surveys, research on vector breeding in industrial settings is limited. Therefore, this research aimed to explore Aedes vector infestation levels in industrial regions, their breeding places and the presence of dengue virus transmission.

Methods: An Aedes immature survey was conducted in 70 industrial units of an urban industrial estate of Puducherry, following standard protocols by the National Centre for Vector Borne Disease Control. The collected immatures were reared for adult emergence and species identification. Larval indices and breeding habitat contribution for Aedes aegypti and Aedes albopictus were carried out. Furthermore, adult traps were set up to detect the presence of Dengue viral RNA in adult mosquitoes. Chi-square statistics were performed to find the association of breeding positivity with industry types and container types.

Results: Aedes breeding was noted in 48 units (68.6%). All industrial types had remarkably high Aedes indices. In industrial areas, Ae aegypti was the most common dengue vector species, followed by Ae. albopictus. Out of the nine major container types, discarded types had a 90% positivity rate. Significant associations were also noted between container positivity and industry type (Χ² 15.7, p < 0.001), mosquito species and industry type (Χ² 16, p = 0.0143) and container type on mosquito breeding (Χ² 48.9, p < 0.001). Molecular analysis showed no detectable levels of dengue virus in the mosquito samples.

Conclusion: Surveillance on Aedes density is important in determining factors related to dengue transmission, in order to prioritise areas and seasons for vector control. Aedes mosquito populations in industrial settings pose a serious threat to public health. Appropriate surveillance and control strategies need to be framed for such large non-residential areas at a policy level. Combining environmental management techniques, innovative vector control methods and community engagement may help reduce the health concerns associated with Aedes in these complex industrial settings.