Application of Wolbachia-based mosquito control in urban open parks

This study aims to explore the application of Wolbachia-transinfected sterile mosquitos (Aedes albopictus) in complex urban open environment to provide scientific evidence for dengue control strategies based on this technology.

From May to November 2023, a pilot project for the release of Wolbachia-transinfected sterile mosquitoes (PAB males) was carried out with Chuihong Park, Chancheng District, Foshan City as the release site, the surrounding communities as the buffer site, and Nanpu Park as the control site. After five weeks of baseline data collection, PAB male mosquitoes were released into the release site and buffer site for 24 and 22 consecutive weeks, respectively, starting in June to control the wild A. albopictus population. Throughout the study, BG-traps and ovitraps were used weekly to collect the data on female density and average hatched-larvae number in the three sites. The reduction rates of these two indicators in the release site and the buffer site were compared to the control site to evaluate the population suppression efficiency of PAB male release. Additionally, the human landing catch method was used to randomly assess the biting index of A. albopictus in the release site and control site over five consecutive months to evaluate the effect of PAB male mosquitoes in controlling the biting rate of A. albopictus in the release site.

From June to November 2023, a total of 8, 150, 400 PAB males were released into the release and buffer sites, with weekly release dose of 8.69 males/m² and 1.13 males/m², respectively. Monitoring data of adults and larvae showed that the release of PAB males achieved a significant suppression effect on the wild A. albopictus population. The suppression efficiency of female A. albopictus in the release and buffer sites was 80.83% and 64.01%, respectively, and the suppression efficiency of larvae was 76.53% and 62.74%, respectively. Comparison of the A. albopictus biting index through human landing catches between the release site and the control site showed that the biting rate of A. albopictus in the release site was significantly lower than that in the control site, with the biting index in the release site steadily decreasing by 88.51% compared to the control site.

The continuous release of PAB males in complex urban open environments can effectively control the population of wild A. albopictus and substantially reduce the mosquito biting rate, effectively mitigating the potential risk of local community transmission of dengue within the target control areas.