Abstract
Introduction: Insecticide resistance is one of the major challenges in vector control programs around the globe. This study investigated the insecticide resistance and kdr mutation in the Anopheles arabiensis malaria vector in Khartoum State, Sudan.
Methods: Entomological cross-sectional surveys were carried out at four urban and suburban sites in Khartoum State. Four insecticides were tested for World Health Organization (WHO) susceptibility, and kdr frequencies were estimated using two allele-specific PCR assays.
Results: WHO bioassay tests revealed that DDT, malathion, and permethrin showed high resistance in both urban and suburban sites. There is no significant difference in mortality rates between urban and suburban sites (P>0.05), with the exception of DDT, where mosquitoes from urban sites showed more susceptibility [64 (51.23-76.77)] than those from suburban areas [53.5 (69.73-95.27)]. In general, all populations from the four sites showed faster KDT50% to bendiocarb and permethrin than to malathion and DDT insecticides. Generalized linear model analysis revealed that insecticide type, site type, and their interaction were determinant factors in mortality rate. A high to moderate frequency of the West African kdr mutation (L1014F) was observed in urban and suburban sites, and the association between the presence of the kdr mutation and resistance phenotype was strong for permethrin and DDT (OR>7 in the allelic test).
Conclusion: This study showed the susceptibility status of the malaria vector A. arabiensis to four insecticides belonging to different classes in urban and suburban sites. This provides important knowledge that helps vector surveillance and control programs. Additionally, more research is necessary to explore the impact of pyrethroid resistance, particularly in bednets, and other resistance mechanisms in this malaria vector.