Wide spread cross resistance to pyrethroids in Aedes aegypti (Diptera: Culicidae) from Veracruz state Mexico
Autor(es): Flores, Adriana E.; Ponce, Gustavo; Silva, Brenda G.; Gutierrez, Selene M.; Bobadilla, Cristina; Lopez, Beatriz; Mercado, Roberto; Black, William C.
Resumo: Seven F-1 strains of Aedes aegypti (L.) were evaluated by bottle bioassay for resistance to the pyrethroids d-phenothrin, permethrin, deltamethrin, lambda-cyalothrin, bifenthrin, cypermethrin, alpha-cypermethrin, and z-cypermethrin. The New Orleans strain was used as a susceptible control. Mortality rates after a 1 h exposure and after a 24 h recovery period were determined. The resistance ratio between the 50% knockdown values (RRKC50) of the F-1 and New Orleans strains indicated high levels of knockdown resistance. The RRKC50 with alpha-cypermethrin varied from 10 to 100 among strains indicating high levels of knockdown resistance. Most of the strains had moderate resistance to d-phenothrin. Significant but much lower levels of resistance were detected for lambda-cyalothrin, permethrin, and cypermethrin. For z-cypermethrin and bifenthrin, only one strain exhibited resistance with RRKC50 values of 10- and 21-fold, respectively. None of the strains showed RRKC50 >10 with deltamethrin, and moderate resistance was seen in three strains, while the rest were susceptible. Mosquitoes from all strains exhibited some recovery from all pyrethroids except d-phenothrin. Regression analysis was used to analyze the relationship between RRLC50 and RRKC50. Both were highly correlated (R-2 = 0.84-0.97) so that the slope could be used to determine how much additional pyrethroid was needed to ensure lethality. Slopes ranged from 0.875 for d-phenothrin (RRLC50 similar or equal to RRKC50) to 8.67 for lambda-cyalothrin (similar to 8.5-fold more insecticide needed to kill). Both RRLC50 and RRKC50 values were highly correlated for all pyrethroids except bifenthrin indicating strong cross-resistance. Bifenthrin appears to be an alternative pyrethroid without strong cross-resistance that could be used as an alternative to the current widespread use of permethrin in Mexico.
Palavras-Chave: Aedes aegypti; Pyrethroids; Insecticide resistance; Cross-resistance
Imprenta: Journal of Economic Entomology, v. 106, n. 2, p. 959-969, 2013
Identificador do objeto digital: 10.1603/EC12284
Descritores: Aedes aegypti - Public health
Data de publicação: 2013
