Anthropogenic factors have contributed to the expansion of the dengue vector Aedes aegypti into previously non-endemic regions. In East Africa, rising dengue cases highlight gaps in understanding the role of Ae. aegypti . Here, we present a molecular characterization of Ae. aegypti in Somaliland following a dengue outbreak. Adult Aedes mosquitoes were collected from Hargeisa, Berbera and Burao. PCR and sequencing were applied to determine species, identify vgsc resistance mutations, and analyze bloodmeal sources. WHO bioassays were also conducted to determine the status of pyrethroid insecticide resistance. Multiple COI haplotypes were identified, with Hargeisa exhibiting the highest diversity. Pyrethroid resistance mutations S989P, V1016G, and F1534C were detected at all locations, with the highest frequency observed in Burao. While no association was observed between allele frequencies and insecticide resistance, resistance was associated with total heterozygous genotypes. The detection of S989P/V1016G mutation combinations, observed mostly in Asia underscores the need for investigations into the origin of uncommon Ae. aegypti lineages into East Africa. Overall, this study reveals the varying utility of molecular markers for species identification and tracking phylogeographic shifts in the distribution of Ae. aegypti lineages. This highlights the need for improved vector control strategies and strengthen surveillance in Somaliland.
Oriyomi et al. (Mon,) studied this question.