Se realizó un estudio de la resistencia a insecticidas en larvas y adultos de Aedes aegypti de 2 provincias del Perú: Trujillo y Tumbes donde prevalecen altos índices de infestación de este vector y están sometidas a extenso uso de insecticidas por la Estrategia de Vigilancia y Control Vectorial del Ministerio de Salud. Los bioensayos en larvas revelaron susceptibilidad al insecticida organofosforado malation (FR50 ≤ 5x) en la cepa TRUJILLO, moderada a fention y fenitrotion (FR50 entre 5 y 10) y alta resistencia (FR50 ≥ 10x) a clorpirifos y temefos, sin embargo en la cepa TUMBES se observó susceptibilidad para los organofosforados evaluados, excepto para fention, con moderada resistencia. En el estado adulto, a la dosis recomendada, en TRUJILLO se observó resistencia al organoclorado DDT y a los piretroides lambdacialotrina y ciflutrina, la cepa TUMBES fue resistente a DDT y a todos los piretroides evaluados. Ninguna de las 2 cepas mostró resistencia a clorpirifos en el estado adulto. Los resultados, utilizando sinergistas, demostraron que las enzimas esterasas y monooxigenasas desempeñaron un papel importante en la resistencia observada a organofosforados en larvas de la provincia TRUJILLO. A través de ensayos bioquímicos se encontró a elevada frecuencia la actividad incrementada de esterasas en TRUJILLO, al igual que la glutation transferasa (GST) y la acetilcolinesterasa modificada (AchE). Mediante electroforesis en gel de poliacrilamida se observó en TRUJILLO, no en TUMBES, la prevalencia de la amplificada actividad de esterasas A4.

Insecticide resistance of Aedes aegypti larvae and adults from two Peruvian provinces, that is, Trujillo and Tumbes provinces, was conducted. High infestation indexes and extensive use of insecticides based on the Vector Surveillance and Control Strategy of the Ministry of Public Health prevailed in these places. Larval bioassays revealed susceptibility to organophosphorate insecticide called malathion in TRUJILLO strain, it being moderate to fention and fenitrotion and high to chlorpyriphos and temephos; however, TUMBES strain was susceptible to the evaluated organophosphorate compounds, except for fention, with moderate resistance. In the adult state, at the recommended dose, TRUJILLO strain showed resistance to DDT organochlorate insecticide and to pyrethoids called lambdacyalotrine and cyflutrine whereas TUMBES was resistent to DDT and to all assessed pyrethoids. None of them was resistent to chlorpiriphos in adult stage. By using synergists, the results showed that esterases and monooxigenases played an important role in the detected resistence to organophosphorate in Aedes larvae from TRUJILLO province. Biochemical assays yielded that increased activity of esterases was very frequent in TRUJILLO strain as was the case of glutathion transferase(GST) and modified acetylcholinesterase (AchR). On the other hand, the polyacrylamide gel electrophoresis allowed observing the prevalence of amplified activity of esterases A4 in TRUJILLO strain but not in TUMBES strain.