Constância F. J. Ayres, Gonçalo Seixas, Sílvia Borrego, Cátia Marques, Inilça Monteiro, Camila S. Marques, Bruna Gouveia, Silvania Leal, Arlete D. Troco, Filomeno Fortes, Ricardo Parreira, João Pinto, Carla A. Sousa
The extensive use of insecticides for vector control has led to the development of insecticide resistance in Aedes aegypti populations on a global scale, which has significantly compromised control actions. Insecticide resistance, and its underlying mechanisms, has been investigated in several countries, mostly in South American and Asian countries. In Africa, however, studies reporting insecticide resistance are rare and data on resistance mechanisms, notably knockdown resistance (kdr) mutations, is scarce. In this study, the recently described V410L kdr mutation is reported for the first time in old world Ae. aegypti populations, namely from Angola and Madeira island. Two additional kdr mutations, V1016I and F1534C, are also reported for the first time in populations from Angola and Cape Verde. Significant associations with the resistance phenotype were found for both V410L and V1016I individually as well as for tri-locus genotypes in the Angolan population. However, no association was found in Madeira island, probably due to the presence of a complex pattern of multiple insecticide resistance mechanisms in the local Ae. aegypti population. These results suggest that populations carrying the same kdr mutations may respond differently to the same insecticide, stressing the need for complementary studies when assessing the impact of kdr resistance mechanisms in the outcome of insecticide-based control strategies.