Resistência do Aedes aegypti ao temefós em Municípios do Estado do Ceará

Abstract

A crescente incidência do dengue nas últimas décadas e o risco de reurbanização da febre amarela requerem estratégias efetivas e eficientes para o enfrentamento desses complexos processos ecológico-epidemiológicos pelos serviços de saúde pública no Brasil. Tradicionalmente, a principal estratégia para o controle do Aedes aegypti tem sido o uso intensivo de inseticidas para a eliminação do mosquito adulto ou de suas larvas. Para o combate ao adulto, utilizam-se com mais Resistência do Aedes aegypti ao Temefós em Municípios do Estado do CearáAedes aegypti resistance to temefos in counties of Ceará State ABSTRACTThe susceptibility of Aedes aegypti to temefos was evaluated by means of samples of eggs and larvae from four large counties in the State of Ceará (Fortaleza, Barbalha, Juazeiro do Norte and Crato). The technique standardized by the World Health Organization for tests with larvicides was used. The CL50 of eight samples from populations of Aedes was determined, as were their respective resistance ratios, compared to the CL50 of the susceptible Rockefeller strain. All populations submitted to the experiment showed resistance to temefos, with resistance ratios varying between 8 and 16. Analysis of these results reinforces prior evidence regarding the dissemination of temefos resistance in different locations in the state, subjected to considerable pressure for control in recent decades. The larvicide may lose its effectiveness if an urgent attempt is not made to reestablish the susceptibility of Aedes aegypti in these areas, profoundly affecting control campaigns currently under way. Key-words: Aedes aegypti. Control of vectors. Temefos. Resistance to insecticides. freqüência os inseticidas organofosforados e piretróides, geralmente durante as epidemias de dengue. No controle de larvas, o principal larvicida, empregado há décadas no país, é o organofosforado temefós, utilizado a 1ppm de princípio ativo, adsorvido em grãos de areia numa formulação contendo 1% dessa substância, que pode ser aplicada em água para o consumo humano, graças à sua baixa toxicidade oral para mamíferos.

Association of insecticide use and alteration on Aedes aegypti susceptibility status

“…aegypti to temephos in many states of Brazil like Espírito Santo , Rio de Janeiro (Braga et al 2004). Also from the Northeast region, resistance to temephos seems to be persistent as it was detected more recently in the state of Paraíba with RR (LC90) higher than 10 in three out of six counties (Beserra et al 2007), and in Ceará (Lima et al 2006). Santos, the only SP population grouped with populations from the Northeast region, is the city with the highest dengue incidence in the state, which means it has been under high selection pressure through intense use of insecticide.…”

“…The opportunity of studying the impact of using different insecticide groups on population susceptibility can help understanding its role in resistance development and it may also support the choice of product use to improve vector control effectiveness. tibility Monitoring Program and sampling methodologies are described in Lima et al (2003Lima et al ( , 2006 and Macoris et al (2003). Nine counties from SP were sampled: Araçatuba, Bauru, Barretos, Campinas, Marília, Presidente Prudente, Ribeirão Preto, São José do Rio Preto, and Santos.…”

Aedes aegypti and Aedes albopictus (Diptera: Culicidae): coexistence and susceptibility to temephos, in municipalities with occurrence of dengue and differentiated characteristics of urbanization

“…Prophiro JS et al -Aedes aegypti and Aedes albopictus: coexistence and temephos susceptibility future 7,8 . This is a problem that can be detected in advance and resulted in the inclusion of this species in the National Network for the Resistance Monitoring of Ae.…”

Phenotypic and genotypic profile of pyrethroid resistance in populations of the mosquito Aedes aegypti from Goiânia, Central West Brazil

“…Vector control is therefore critical for public health (1) . Worldwide, pyrethroids (PYs) are the most common class of insecticides used to control adult insects (2) . However, prolonged use of these insecticides has resulted in the evolution of PY-resistant mosquito populations in many countries, including Brazil (3) (4) .…”