Vol. 6, Issue 1, Part B (2024)

Background: Resistance in Anopheles mosquitoes to at least one class of insecticides is reported in 90% of malaria-endemic countries. There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This trend of rapid increase in observed insecticide resistance following exposures is alarming as it reduces our overall chemical arsenal to control disease vectors and the efficacy of many vector control products that have been and will be deployed. Furthermore; there is limited information on insecticide susceptibility status of human-biting mosquitoes in Eritrea. This study aimed to determine insecticide susceptibility status of human biting mosquitoes in an urban area of western Eritrea.
Methods: The study was conducted in Tesseney district, Eritrea in which the Entomology laboratory center located. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on four days old human biting mosquitoes. Each mosquito was exposed to three classes of insecticides at different concentrations commonly used for IRS & LLINs. 1-hour knockdown and 24 hours’ mortality rates (%) post insecticide exposure were determined.
Results: Mosquito type tested were belongs to Anopheles, culex and Aedes. Aedes mosquitoes were susceptible to all tested insecticides except to pirimiphosmethyl (0.25%). Anopheles mosquitoes has found resistant to Pirimiphosmethyl (0.25%), Alpha cypermethrine (0.05), possible resistance to Alpha cypermethrine (0.25%, 0.5%)and bendiocarb 0.1%, but showed susceptible to Pirimiphosmethyl (1.25%, 2.25%) bendiocarb (0.5%,1%). our finding shown, culex mosquitoes were resistant to all tested insecticides except susceptible with Pirimiphosmethyl (2.25%) and Alpha cypermethrine (0.5) and possible resistance to Alpha cypermethrine (0.25%).
Conclusion: Our results revealed that different type of mosquitoes had different susceptibility status to different class of Insecticide commonly used for IRS and LLINs in our area. The current susceptibility status of the tested mosquitoes showing the need to select the most efficacious insecticide for the least susceptible mosquito species to achieve successful mosquito control.