The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites.

Dengue and dengue hemorrhagic fever, vector-borne diseases transmitted by the mosquito Aedes aegypti, are presently important public health problems in Brazil. As the strategy for disease control is based on vector control through the use of insecticides, the development of resistance is a threat to programs efficacy. The objective of this study was to compare the Aedes aegypti susceptibility in nine vector populations from the state of São Paulo and seven from Northeast region of Brazil, since there was a difference on group of insecticide used between the areas. Bioassays with larvae and adult were performed according to the World Health Organization methods.The results showed higher resistance levels to organophosphates group in populations from the Northeast region where this group was used for both larvae and adult control than in São Paulo where organophosphates were used for larvae and pyretroids for adult control. Resistance to pyretroids in adults was widespread in São Paulo after ten years of use of cypermethrin while in vector populations from the Northeast region it was punctual. The difference in resistance profile between the areas is in accordance to the group of insecticide used.

OBJETIVO: Avaliar a ocorrência de população adulta de culicídeos em área urbana e medir a sensibilidade do método de coleta em caixa de repouso MÉTODOS: Foram coletados mosquitos entre 1999 e 2000, em duas cidades do Estado de São Paulo: Ocauçu e Uchoa. Em cada uma delas, sortearam-se 15 quadras, e em cada quadra um domicílio, onde foram instaladas duas caixas de repouso, no intra e no peridomicílio. Realizaram-se coletas mensais por domicílio, durante 13 meses, utilizando aspiradores manuais no intra e peridomicílio e no interior das caixas. Os espécimes capturados foram levados ao laboratório para triagem e identificação por espécie e sexo. RESULTADOS: Dos 2.112 espécimes de culicídeos coletados, 99,7% corresponderam a quatro espécies: Culex quinquefasciatus, Aedes aegypti, Cx. declarator e Cx. coronator. A distribuição percentual dessas espécies foi, respectivamente, em Ocauçu: 83,3%, 3,2%, 10,8% e 2,4%, e em Uchoa: 83,8%, 8,4%, 4,4% e 3,0%. Das fêmeas do gênero Culex, 34,3% foram coletadas nas caixas de repouso e 59,9% encontravam-se no intradomicílio. Das fêmeas de Ae. aegypti, 17,6% foram coletadas nas caixas de repouso e 82,4% encontraram-se no intradomicílio. CONCLUSÕES: A grande maioria dos espécimes coletados pertenciam a quatro espécies de culicídeos, sendo Cx. quinquefasciatus a mais freqüente. Proporcionalmente, as fêmeas de Ae. aegypti ocuparam mais o intradomicílio do que as do gênero Culex. A caixa de repouso apresenta potencial de utilização como dispositivo de vigilância, mas precisa ser mais bem avaliada.

OBJECTIVE: To evaluate the occurrence of adult culicid populations in urban areas and measure the sensitivity of the resting box collection method. METHODS: Mosquito were collected in 1999 and 2000, in two cities in the State of São Paulo, Brazil: Ocauçu and Uchoa. In each city, 15 blocks were drawn by lots and then one home in each block was drawn. Two resting boxes were installed at each home: one inside and the other outside the house. Monthly collections were carried out at each home, over a 13-month period, using manual aspirators inside and outside the home and inside the boxes. The captured specimens were taken to the laboratory for screening and identification according to species and sex. RESULTS: Out of the 2,112 culicid specimens collected, 99.7% were of four species: Culex quinquefasciatus, Aedes aegypti, Cx. declarator and Cx. coronator. The distribution of these species in Ocauçu was 83.3%, 3.2%, 10.8% and 24%, respectively, and in Uchoa it was 83.8%, 8.4%, 4.4% and 3.0%, respectively. Among the females of the genus Culex, 34.3% were captured in the resting boxes and 59.9% were collected from inside the house. Among the females of Ae. aegypti, 17.6% were found in the resting boxes and 82.4% inside the home. CONCLUSIONS: The great majority of the specimens collected belonged to four species of culicids, and Cx. quinquefasciatus was the most common. Proportionally, the females of Ae. aegypti were found more inside the home than were those of the genus Culex. Resting boxes present potential for use as surveillance devices, but their use needs to be more thoroughly evaluated.

OBJETIVO: Avaliar a ocorrência de população adulta de culicídeos em área urbana e medir a sensibilidade do método de coleta em caixa de repouso MÉTODOS: Foram coletados mosquitos entre 1999 e 2000, em duas cidades do Estado de São Paulo: Ocauçu e Uchoa. Em cada uma delas, sortearam-se 15 quadras, e em cada quadra um domicílio, onde foram instaladas duas caixas de repouso, no intra e no peridomicílio. Realizaram-se coletas mensais por domicílio, durante 13 meses, utilizando aspiradores manuais no intra e peridomicílio e no interior das caixas. Os espécimes capturados foram levados ao laboratório para triagem e identificação por espécie e sexo. RESULTADOS: Dos 2.112 espécimes de culicídeos coletados, 99,7% corresponderam a quatro espécies: Culex quinquefasciatus, Aedes aegypti, Cx. declarator e Cx. coronator. A distribuição percentual dessas espécies foi, respectivamente, em Ocauçu: 83,3%, 3,2%, 10,8% e 2,4%, e em Uchoa: 83,8%, 8,4%, 4,4% e 3,0%. Das fêmeas do gênero Culex, 34,3% foram coletadas nas caixas de repouso e 59,9% encontravam-se no intradomicílio. Das fêmeas de Ae. aegypti, 17,6% foram coletadas nas caixas de repouso e 82,4% encontraram-se no intradomicílio. CONCLUSÕES: A grande maioria dos espécimes coletados pertenciam a quatro espécies de culicídeos, sendo Cx. quinquefasciatus a mais freqüente. Proporcionalmente, as fêmeas de Ae. aegypti ocuparam mais o intradomicílio do que as do gênero Culex. A caixa de repouso apresenta potencial de utilização como dispositivo de vigilância, mas precisa ser mais bem avaliada.

OBJECTIVE: To evaluate the occurrence of adult culicid populations in urban areas and measure the sensitivity of the resting box collection method. METHODS: Mosquito were collected in 1999 and 2000, in two cities in the State of São Paulo, Brazil: Ocauçu and Uchoa. In each city, 15 blocks were drawn by lots and then one home in each block was drawn. Two resting boxes were installed at each home: one inside and the other outside the house. Monthly collections were carried out at each home, over a 13-month period, using manual aspirators inside and outside the home and inside the boxes. The captured specimens were taken to the laboratory for screening and identification according to species and sex. RESULTS: Out of the 2,112 culicid specimens collected, 99.7% were of four species: Culex quinquefasciatus, Aedes aegypti, Cx. declarator and Cx. coronator. The distribution of these species in Ocauçu was 83.3%, 3.2%, 10.8% and 24%, respectively, and in Uchoa it was 83.8%, 8.4%, 4.4% and 3.0%, respectively. Among the females of the genus Culex, 34.3% were captured in the resting boxes and 59.9% were collected from inside the house. Among the females of Ae. aegypti, 17.6% were found in the resting boxes and 82.4% inside the home. CONCLUSIONS: The great majority of the specimens collected belonged to four species of culicids, and Cx. quinquefasciatus was the most common. Proportionally, the females of Ae. aegypti were found more inside the home than were those of the genus Culex. Resting boxes present potential for use as surveillance devices, but their use needs to be more thoroughly evaluated.

Foi detectada, por meio de bioensaios, alteração dos níveis de suscetibilidade do Aedes aegypti a organofosforados em municípios do Estado de São Paulo

Baseline data on susceptibility of Aedes aegypti to organophosphates detected alterations in cities of the state of S. Paulo, Brazil

Foi detectada, por meio de bioensaios, alteração dos níveis de suscetibilidade do Aedes aegypti a organofosforados em municípios do Estado de São Paulo

Baseline data on susceptibility of Aedes aegypti to organophosphates detected alterations in cities of the state of S. Paulo, Brazil