Population genetic dynamics of dengue vectors Aedes aegypti and Aedes albopictus in Sri Lanka: baseline study for designing Wolbachia control method

Abstract

Dengue is an arboviral disease transmitted principally by two vectors Aedes aegypti and Aedes albopictus. In the absence of a successful prophylaxis or treatment, the disease control relies solely on vector control. Therefore, the knowledge on vector population genetics can play an important role in designing efficient vector control strategies especially during the release of Wolbachia transinfected mosquitoes. As such, we investigated the population genetic structure of Ae. aegypti and Ae. albopictus in Sri Lanka covering seven (Colombo, Gampaha, Kalutara, Galle, Jaffna, Mullathivu and Kilinochchi) dengue endemic regions using six microsatellite markers specific for each species to provide baseline data to implement Wolbachia control method. According to the results, both species revealed small but significant population structure. The genetic structure observed for Ae. albopictus populations was more subtle compared to that of Ae. aegypti reflecting their comparatively high geneflow over long distances. Evidence for possible multiple invasions towards the northern part of the country from the southern Ae. albopictus populations facilitated by increased human activity and urbanization were also apparent. On the contrary, the dispersal of Ae. aegypti was observed to be more restricted especially between north and south parts of the country. The genetic diversity and effective population number was also greater for Ae. albopictus compared to Ae. aegypti indicating their relatively higher evolutionary potential and adaptability. As a whole, our study suggests that the scheduled dengue control measurers using Wolbachia infected mosquitoes need to cover both vector species based on their species specific geneflow patterns to yield an effective dengue control.