Evaluation of the Efficacy of In2Care Mosquito Station against an invasive malaria vector Anopheles stephensi in Awash Sebat kilo, Afar Region, Ethiopia

Abstract

The invasive, insecticide-resistant Anopheles stephensi mosquito poses a growing malaria threat in urban Africa. Declining efficacy of conventional chemical controls necessitates alternative strategies. This study evaluated the In2Care Mosquito Station's effectiveness against An. stephensi in Awash Sebat Kilo, Afar, and Ethiopia. Thirty In2Care stations were deployed in suitable locations near human habitation and vegetated area. Ovitraps were placed next to each In2care stations to monitor larval densities and PPF auto-dissemination effects. In2Care stations were serviced every six weeks, and weekly larval counts were conducted. Water samples were collected and monitored for larval development, focusing on the L3 stage. An. stephensi larvae are added to observe development until emergence or death. Additionally, WHO tube were used for both In2mixsachet and control, unfed An. stephensi females were selected from the rearing cage and exposed for 3 minutes to test adulticide effects. The exposed mosquitoes were transferred to a cleaned paper cup, provided with sugar source food, and monitored. The data was analyzed using Excel and EMBSPSS. Results showed that the In2Care stations effectively attracted mosquitoes, as indicated by increased larval counts in treatment stations (P<0.05). The deployment of In2care stations as a new treatment has resulted in trapping of a higher mean number of larvae compared to the control, suggesting that PPF's mosquito’s attraction is effective (a p<0.05). The larvicide test revealed that while control larvae developed into adults, those in the treatment larvae died at the pupal stages, indicating PPF inhibits adult emergence. The auto-dissemination test showed that 71.7% of larvae did not emerge to adults which is significantly different. Beauveria bassiana also significantly impacted adult mosquito mortality, ranging from 12% to 100% by day 9, compared to controls. In2care Mosquito Station proves to be an effective outdoor insecticide method, utilizing slow-killing larvicide to attract and destroy mosquitoes, impacting both larvae and adults, and reducing breeding opportunities in containers, thus lowering vector population. The study highlights the critical importance of exploring and implementing innovative vector control methods, such as the In2Care system, in regions grappling with the challenges posed by invasive mosquito species and insecticide resistance.