In Saudi Arabia, the effectiveness of controlling dengue vectors is being greatly compromised by insecticide resistance (IR). This study investigates the status and levels of IR in Aedes aegypti (L., 1762) (Diptera: culicidae) in response to deltamethrin in Gizan City, Jazan region, southwestern (SW) Saudi Arabia. Larvae and pupae were collected using the dipping method during the winter season (Nov. 2021 to January 2022) from different breeding sites in the Gizan City, transferred to the insectary of the Saudi Center for Disease Prevention and Control (SCDC), and maintained under rearing conditions until the adult stage. Female mosquitoes, aged 2 to 5 days, were exposed to the World Health Organization (WHO) diagnostic dose (1×DD) of deltamethrin (0.05%) to assess baseline susceptibility. For populations exhibiting resistance at the diagnostic dose, an increased concentration equivalent to five times the diagnostic dose (5×DD; 0.25%) was applied to determine resistance intensity in accordance with WHO insecticide resistance (IR) intensity bioassay guidelines. The mortality rate for deltamethrin (0.05%) at the diagnostic dose 1×DD was 91%, which is below the 98% susceptibility threshold.
Assessment of resistance intensity indicated a low level of resistance in Aedes aegypti populations from Gizan City, with 98% mortality observed at 5×DD.
The present study indicates a low level of resistance to deltamethrin in the Gizan City. These results provide policymakers crucial information in designing and implementing effective insecticide resistance management (IRM) strategies. Further research is warranted to assess the efficacy and underlying mechanisms of resistance, particularly the role of the synergist piperonyl butoxide (PBO), in enhancing the control of pyrethroid-resistant dengue vectors.
International Journal of Mosquito Research
