Potential of ivermectin as an active ingredient of the attractive toxic sugar baits against the Indian malaria vectors Anopheles culicifacies and Anopheles stephensi.

BACKGROUND

Attractive toxic sugar bait (ATSB) is a novel vector control tool that exploits the sugar feeding behavior of mosquitoes. The current study aims to evaluate the efficacy of ivermectin-based ATSB against insecticide susceptible and resistant strains of major Indian malaria vectors - Anopheles culicifacies and Anopheles stephensi. ATSB with different concentrations of ivermectin were tested against mosquito vectors under standard laboratory conditions.

RESULTS

Dose-response analysis of ivermectin-ATSB showed 7.8 and 19.8 ppm as 50% and 90% lethal concentration (LC and LC ) values for insecticide susceptible An. culicifacies. In the case of insecticide susceptible An. stephensi, the LC value was 35 ppm which was significantly higher in comparison to the LC for An. culicifacies. The LC of insecticide-resistant An. culicifacies and An. stephensi were 10.6 and 15.9 ppm respectively whereas LC values were 36.9 and 61.0. Ivermectin-ATSB resulted in 99 ± 0.8% mortality of An. culicifacies and 93 ± 3.8% mortality of An. stephensi at an ivermectin concentration of 25 ppm. In another set of experiments, the ATSB solution containing standardized dose of ivermectin was sprayed on Allysum plant and mortality of both Anopheline vectors was recorded. Here, we observed > 90% mortality in both An. stephensi and An. culicifacies.

CONCLUSION

Our study demonstrates the potential of ivermectin-based ATSB in killing Indian malaria vectors irrespective of the method of application. Further field trials with ivermectin containing ATSB may pave the way for its usage in the national vector control program. © 2022 Society of Chemical Industry.