<![CDATA[Aedes aegypti (Linnaeus) is the primary vector of dengue virus. Prolonged and widespread use of insecticides, particularly pyrethroids for household vector control, has led to increasing insecticide resistance in Ae. aegypti populations. Cuticle thickening has been reported as a resistance mechanism, yet evidence for this mechanism in Ae. aegypti from Indonesia is still limited. This study aimed to investigate cuticle thickening in pyrethroid-resistant Ae. aegypti populations from Gunung Pangilun Village, Padang City, West Sumatra, Indonesia. Mosquito samples were collected using egg traps (ovitraps) and reared until the adult stage. Susceptible and resistant populations were determined by a WHO-based bioassay with impregnated paper 0.025% alpha-cypermethrin, collecting 10 individuals per group, and cuticle thickness was measured at the mid-tibia using scanning electron microscopy (SEM). The results found that cuticle thickness in the resistant group was 1.28-fold thicker than that in the susceptible group. This study suggests the involvement of cuticular penetration resistance, which may reduce the efficacy of contact insecticides such as pyrethroids, as well as provides initial evidence supporting cuticle thickening in pyrethroid-resistant Ae. aegypti from Indonesia. These findings emphasize the need to strengthen resistance management strategies, insecticide rotation, and integrated vector control approaches to reduce further increases in resistance.]]>
