Effective Aedes mosquito reduction through In2Care interventions in an extreme environment

In2Care traps combining an insect growth regulator (pyriproxyfen) with an entomopathogen (Beauveria bassiana) have been developed as an effective way of reducing mosquito populations with promising results. Here, we test the technology in Jeddah, Saudi Arabia, against Aedes aegypti mosquitoes. In2Care traps might be particularly suitable in Jeddah because harsh climatic conditions in the hot dry season may limit Aedes movement when mosquitoes likely persist in localized sites around underground car parks and other built structures. After 8 wk of deployment, the proportion of positive traps in the intervention area was gradually reduced by 39% in the unfavorable season compared with a control area. No adults emerged from In2Care traps. Breeding containers placed in the trial site, 3 wk after termination of the trial, showed a range of emergence values from 0 to 100% compared with controls where emergence was always >80%. In subsequent interventions in three other sites, we obtained reductions of 30% to 52% based on positive traps and egg numbers per trap. However, the intervention did not reduce numbers at one site which was expected to be a mosquito hotspot and subsequently shown to have an estimated mosquito population 5.2× larger than the adjacent control area. The clear reduction at some sites and an increasing reduction in numbers over time at others, several weeks after post-In2Care monitoring operations were completed, highlight the potential of the In2Care approach in this environment. The approach could help to reduce routine pesticide-based fogging that forms the mainstay of current control measures in Jeddah.