Captura de culicídeos em área urbana: avaliação do método das caixas de repouso / Capture of culicids in urban areas: evaluation of the resting box method

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 por cento corresponderam a quatro espécies: Culex quinquefasciatus, Aedes aegypti, Cx. declarator e Cx. coronator. A distribuição percentual dessas espécies foi, respectivamente, em Ocauçu: 83,3 por cento, 3,2 por cento, 10,8 por cento e 2,4 por cento, e em Uchoa: 83,8 por cento, 8,4 por cento, 4,4 por cento e 3,0 por cento. Das fêmeas do gênero Culex, 34,3 por cento foram coletadas nas caixas de repouso e 59,9 por cento encontravam-se no intradomicílio. Das fêmeas de Ae. aegypti, 17,6 por cento foram coletadas nas caixas de repouso e 82,4 por cento 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 percent were of four species: Culex quinquefasciatus, Aedes aegypti, Cx. declarator and Cx. coronator. The distribution of these species in Ocauçu was 83.3 percent, 3.2 percent, 10.8 percent and 24 percent, respectively, and in Uchoa it was 83.8 percent, 8.4 percent, 4.4 percent and 3.0 percent, respectively. Among the females of the genus Culex, 34.3 percent were captured in the resting boxes and 59.9 percent were collected from inside the house. Among the females of Ae. aegypti, 17.6 percent were found in the resting boxes and 82.4 percent 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.

[Capture of culicids in urban areas: evaluation of the resting box method]. / Captura de culicídeos em área urbana: avaliação do método das caixas de repouso.

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.

Resistance of Aedes aegypti from the state of São Paulo, Brazil, to organophosphates insecticides.

Since the reintroduction of Aedes aegypti in the state of S o Paulo, in the middle of the 1980-decade, organophosphate insecticides are being used to control the dengue vector. In 1996, an annual program for monitoring the susceptibility of Ae. aegypti to the insecticides was implemented. Some of the results of this monitoring program are presented. Ae. aegypti populations from ten localities have been submitted to bioassays with the diagnostic dose of temephos and fenitrothion. Only two (Mar lia and Presidente Prudente) remain susceptible to both insecticides and one (Santos) exhibits true resistance. Ae. aegypti from the remaining localities showed an incipient altered susceptibility. Resistance ratios varied from 1.2 to 2.9 for temephos and from 1.5 to 3.2 to fenitrothion, indicating moderate levels of resistance. Biochemical assays did not detect alterations in the enzyme acetilcholinesterase, but indicated that resistance is associated with esterases.

Resistance of Aedes aegypti from the state of Säo Paulo, Brazil, to organophosphates insecticides

Since the reintroduction of Aedes aegypti in the state of Säo Paulo, in the middle of the 1980-decade, organophosphate insecticides are being used to control the dengue vector. In 1996, an annual program for monitoring the susceptibility of Ae. aegypti to the insecticides was implemented. Some of the results of this monitoring program are presented. Ae. aegypti populations from ten localities have been submitted to bioassays with the diagnostic dose of temephos and fenitrothion. Only two (Marília and Presidente Prudente) remain susceptible to both insecticides and one (Santos) exhibits true resistance. Ae. aegypti from the remaining localities showed an incipient altered susceptibility. Resistance ratios varied from 1.2 to 2.9 for temephos and from 1.5 to 3.2 to fenitrothion, indicating moderate levels of resistance. Biochemical assays did not detect alterations in the enzyme acetilcholinesterase, but indicated that resistance is associated with esterases

Vector competence of Brazilian Aedes aegypti and Ae. albopictus for a Brazilian yellow fever virus isolate.

Because the potential urban yellow fever (YF) mosquito vectors Aedes aegypti and Ae. albopictus are at historical highs in Brazil, both in terms of density and geographical range, we assessed the risk of an urban YF epidemic in Brazil. We evaluated and confirmed in a laboratory setting the vector competence of Brazilian Ae. aegypti for a currently circulating strain of YF virus, and investigated the potential for Brazilian Ae. albopictus to transmit YF.

Alteraçäo de resposta de suscetibilidade de Aedes aegypti a inseticidas organofosforados em municípios do Estado de Säo Paulo, Brasil / Alteration in susceptibility response of Aedes aegypti to organophosphates in cities in the state of S. Paulo, Brazil

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