Impact of environmental temperatures on resistance to organophosphate insecticides in Aedes aegypti from Trinidad.

Autor(es): Polson Karen A; Brogdon William G; Rawlins Samuel C; Chadee Dave D

Resumo: To examine the effects of increasing larval rearing temperatures on the resistance status of Trinidadian populations of Aedes aegypti to organophosphate (OP) insecticides. In 2007-2008, bioassays and biochemical assays were conducted on A. aegypti larvae collected in 2006 from eight geographically distinct areas in Trinidad (Trinidad and Tobago). Larval populations were reared at four temperatures (28 ? 2?C, 32?C, 34?C, and 36?C) prior to bioassays with OP insecticides (fenthion, malathion, and temephos) and biochemical assays for esterase enzymes. Most larval populations reared at 28 ? 2?C were susceptible to fenthion (>98% mortality) but resistant to malathion and temephos (< 80% mortality). A positive association was found between resistance to OP insecticides and increased activities of ?- and ?-esterases in larval populations reared at 28 ? 2?C. Although larval populations reared at higher temperatures showed variations in resistance to OPs, there was a general increase in susceptibility. However, increases or decreases in activity levels of enzymes did not always correspond with an increase or decrease in the proportion of resistant individuals reared at higher temperatures. Although global warming may cause an increase in dengue transmission, based on the current results, the use of insecticides for dengue prevention and control may yet be effective if temperatures increase as projected.

Palavras-Chave: Culicidae; Aedes; Mosquito control; Insecticide resistance; Insecticides; Organophosphate; Temperature; Trinidad and Tobago

Imprenta: Revista Panamericana de Salud Pu?blica, v. 32, n. 1, p. 1-8, 2012

Descritores: Aedes aegypti - Proteins ; Aedes aegypti - Viral infections ; Aedes aegypti - Transmission ; Aedes aegypti - Dengue ; Aedes aegypti - Public health

Data de publicação: 2012