Susceptibility status of malaria vector Anopheles gambiae in settlement villages of southwestern ethiopia

Long-lasting insecticidal treated nets (LLINs) and indoor residual spraying (IRS) are the main vector control interventions in Ethiopia for malaria control. This study evaluates the susceptibility status of principal malaria vector Anopheles gambiae sensu lato against the most widely used insecticides in the study areas. Mosquito larvae were collected using a standard dipper from breeding sites, including rain water collection pools, road pot holes, hoof prints around swamps at Bena and Kusaye villages from May up to June 2018 in Darimu district. Insecticide susceptibility bioassays were performed according to standard guidelines. The findings revealed that A. gambiae is resistant to malathion (5%), deltamethrin (0.05%), and DDT) (4%) but susceptible to propoxur (0.1%) and bendiocarb (0.1%). Knock down time at 50 min (K_DT50) and at 90 min (K_DT90) values of DDT) were very high- 59.37 (57.37–73.46) and 110.59 (96.25–135.09), while K_DT50 and K_DT90 values of malathion were from 77.42 (69.32–90.48) to 125.58 (108.15–154.78), respectively. Since the current study was conducted in the newly formed resettlement area, almost similar trends of resistance to DDT, malathion and deltamethrin were observed.