Caffeine effect on mortality and oviposition in successive generations of Aedes aegypti

OBJECTIVE: Previous experiments showed that caffeine blocks the development of Aedes aegypti (Diptera, Culicidae) in the larval stage, consequently inhibiting the production of adults. This study aimed at obtaining data suggestive of caffeine resistance by these mosquitoes. METHODS: Experiments were carried out in successive generations to assess adult production from eggs laid in previous generation and oviposition rate in every generation using 200 and 500 ��g/mL caffeine. Tap water was used as control. Experiments were conducted in the city of S��o Jos�� do Rio Preto, Southeastern Brazil between 2002 and 2005. Statistical tests consisted of exploratory data analysis and smoothing algorithms. RESULTS: Increasing reduction in productivity of adults occurred among generations at both caffeine concentrations but the differences were only significant at 200��g/mL caffeine. As for the oviposition rate, there was a decrease in the mean number of eggs per female over generations at both caffeine concentrations. CONCLUSIONS: There was no evidence of caffeine resistance over generations. The study results corroborate caffeine as an alternative as an important Ae. Aegypti control agent to avoid resistance.

Sazonalidade de Aedes albopictus em ��rea protegida na cidade de S��o Paulo, Brasil

O estudo teve por objetivo analisar a sazonalidade de Aedes albopictus e a influ��ncia de fatores ambientais em criadouros, em uma ��rea urbana protegida. Foram realizadas coletas de indiv��duos imaturos por suc����o do l��quido de nove ocos de ��rvores, no Parque Ecol��gico do Tiet��, no Munic��pio de S��o Paulo, SP, de 2001 a 2002 . Os resultados do ��ndice de positividade e do n��mero de indiv��duos foram: positividade x precipita����o (ro=0,69; p<0,001); positividade x temperatura (ro=0,35; p<0,001); n��mero de indiv��duos x precipita����o (ro=0,29; p<0,001) e n��mero de indiv��duos x temperatura (ro=0,13; p<0,05). As correla����es sugerem que as chuvas foram mais influentes que a temperatura.

Compet��ncia de peixes como predadores de larvas de Aedes aegypti, em condi����es de laborat��rio

OBJETIVO: Avaliar a compet��ncia de peixes na preda����o de larvas de Aedes aegypti, em condi����es de laborat��rio. M��TODOS: Foram testados machos e f��meas de cinco esp��cies de peixe. Os testes de preda����o duravam cinco semanas para cada esp��cie. Cada ensaio compreendia quatro caixas testes e quatro caixas controles. Das caixas controle, duas tinham somente um peixe e as outras duas, apenas larvas. Cada caixa teste continha um peixe e larvas. Na primeira semana foram expostas 100 larvas em cada caixa, e a cada semana acrescentavam-se 100 larvas por caixa/dia, at�� se obter um m��ximo de 500 larvas/dia. Comprimento e peso dos peixes foram medidos semanalmente. RESULTADOS: Foram utilizadas 369.000 larvas no total. O Trichogaster trichopteros foi a ��nica esp��cie em que ambos os sexos predaram 100% das larvas oferecidas. O Betta splendens deixou de predar apenas 15 larvas. Machos do Poecilia reticulata apresentaram baixa capacidade larv��faga quando comparados ��s f��meas da mesma esp��cie. Em rela����o ao peso e tamanho o Betta splendens mostrou-se capaz de predar 523 larvas/grama/dia. CONCLUS��ES: F��meas e machos de Trichogaster trichopteros e de Astyanax fasciatus, e f��meas de Betta splendens e de Poecillia sphenops foram os peixes que apresentaram maior compet��ncia para predar as larvas. Embora com compet��ncia menor, machos de Poecillia sphenops e f��meas de Poecilia reticulata foram capazes de eliminar o n��mero de larvas de Aedes aegypti que possam emergir durante 24 horas num criadouro, em condi����es naturais. Machos de Poecilia reticulata n��o foram predadores eficazes.

V��rus dengue em larvas de Aedes aegypti e sua din��mica de infesta����o, Roraima, Brasil

OBJETIVO: Identificar a presen��a do v��rus dengue em formas larvais de Aedes aegypti e relacionar a presen��a do vetor com ��ndice pluviom��trico e n��mero de casos de dengue. M��TODOS: Dezoito domic��lios foram selecionados aleatoriamente para coleta de ovos em um bairro da cidade de Boa Vista (RR). Foram instaladas duas ovitrampas por domic��lio e removidas ap��s uma semana, mensalmente, de novembro de 2006 a maio de 2007. Foram calculados o ��ndice de positividade de ovitrampa e o ��ndice de densidade dos ovos. Ap��s eclos��o de 1.422 ovos coletados, foram formados 44 pools de no m��ximo 30 larvas para teste de presen��a do v��rus dengue por meio de RT-PCR e hemi-nested PCR. O ��ndice de incid��ncia de dengue no per��odo foi correlacionado com a precipita����o pluvial. A associa����o entre essas vari��veis e n��mero de ovos coletados foi analisada pelo coeficiente de Pearson. RESULTADOS: Nenhum dos pools apresentou positividade para o v��rus dengue, apesar do bairro ter apresentado elevados ��ndices de incid��ncia de dengue no per��odo estudado. A densidade da popula����o de Ae. aegypti aumentou conforme a pluviosidade, mas n��o apresentou correla����o com ��ndices de incid��ncia de casos de dengue. CONCLUS��ES: Os resultados sugerem que a transmiss��o transovariana do v��rus em mosquitos ocorre a uma freq����ncia muito baixa e por isso sua persist��ncia em meio urbano pode n��o depender desse fen��meno. A popula����o do mosquito aumentou no per��odo de chuvas devido �� forma����o de criadouros; a n��o-correla����o com o ��ndice de incid��ncia de dengue deve-se �� possibilidade desse dado ser subestimado em per��odos de epidemia.

Presumed unconstrained dispersal of Aedes aegypti in the city of Rio de Janeiro, Brazil

OBJECTIVE: To evaluate dispersal of Aedes aegypti females in an area with no container manipulation and no geographic barriers to constrain mosquito flight. METHODS: A mark-release-recapture experiment was conducted in December 2006, in the dengue endemic urban district of Olaria in Rio de Janeiro, Southeastern Brazil, where there is no evident obstacle to the dispersal of Ae. aegypti females. Mosquito traps were installed in 192 houses (96 Adultraps and 96 MosquiTRAPs). RESULTS: A total of 725 dust-marked gravid females were released and recapture rate was 6.3%. Ae. aegypti females traveled a mean distance of 288.12 m and their maximum displacement was 690 m; 50% and 90% of females flew up to 350 m and 500.2 m, respectively. CONCLUSIONS: Dispersal of Ae. aegypti females in Olaria was higher than in areas with physical and geographical barriers. There was no evidence of a preferred direction during mosquito flight, which was considered random or uniform from the release point.

Desigualdade social, crescimento urbano e hansen��ase em Manaus: abordagem espacial

OBJETIVO: Analisar a epidemiologia de hansen��ase segundo a distribui����o espacial e condi����es de vida da popula����o. M��TODOS: Estudo ecol��gico baseado na espacializa����o da hansen��ase em Manaus (AM), entre 1998 e 2004. Os 4.104 casos obtidos do Sistema de Informa����es de Agravos de Notifica����o foram georreferenciados de acordo com a localiza����o dos endere��os em 1.536 setores censit��rios urbanos, por meio de quatro t��cnicas: correios (73,7% dos endere��os encontrados); Programa de Cadastro de Logradouros (7,3%); Programa Sa��de da Fam��lia (2,1%) e folhas de coleta do Instituto Brasileiro de Geografia e Estat��stica (1,5%). Para c��lculo do coeficiente de detec����o utilizou a popula����o de 2001. Na an��lise espacial foi aplicado o m��todo bayesiano emp��rico local para produzir uma estimativa do risco da hansen��ase, suavizando o efeito da flutua����o das taxas, quando calculadas para pequenas ��reas. Para an��lise da associa����o entre espacializa����o e fatores de risco empregou-se a regress��o log��stica, tendo como vari��veis explicativas a ocorr��ncia de casos em menores de 15 anos (indicador de gravidade) e o ��ndice de Car��ncia Social constru��do a partir das vari��veis do Censo 2000. RESULTADOS: O coeficiente de detec����o apresentou-se hiperend��mico em 34,0% dos setores e muito alto em 26,7%. A medida de associa����o (odds ratio) referente ��s vari��veis explicativas foi significativa. A combina����o de baixa condi����o de vida e ocorr��ncia em menores de 15 anos foi adotada para identificar as ��reas priorit��rias para interven����o. CONCLUS��ES: A an��lise espacial da hansen��ase mostrou que a distribui����o da doen��a �� heterog��nea, atingindo mais intensamente as regi��es habitadas por grupos em situa����o de maior vulnerabilidade.

Oviposici��n diaria de Aedes aegypti en Or��n, Salta, Argentina

El objetivo del estudio fue determinar los horarios de m��xima actividad de oviposici��n de Aedes aegypti en la ciudad de Or��n (noroeste argentino). Se realizaron muestreos quincenales entre noviembre de 2006 y febrero de 2007 (primavera-verano). La ciudad fue dividida en tres zonas (norte, centro, sur), donde fueron seleccionadas al azar las viviendas para colocar dos ovitrampas en el exterior de las mismas. Las ovitrampas fueron reemplazadas cada cuatro horas, desde la ma��ana (8h) hasta el atardecer (20h). Se registr�� la mayor cantidad de huevos entre las 16 y 20 h (81%). Estos datos aportan al conocimiento del vector y, por lo tanto, de la posibilidad de control, pudiendo realizarse las fumigaciones en la franja horaria con mayor actividad de oviposici��n.

M��ltipla autoria: crescimento ou bolha inflacion��ria?

OBJETIVO: Analisar o aumento do n��mero de autores por artigo em revistas cient��ficas brasileiras de sa��de coletiva. M��TODOS: Foram pesquisados na base de dados LILACS artigos publicados em seis revistas de sa��de coletiva e uma revista m��dica (para compara����o), da cole����o SciELO, com classifica����o Qualis, da Capes, igual ou superior a B-1, entre 1999 e 2010. Foram avaliadas a evolu����o da mediana de n��meros de autores/artigo e a propor����o de artigos com mais de quatro autores. Estimou-se a associa����o entre o tri��nio de publica����o e a presen��a de quatro ou mais autores por artigo por meio de odds ratio de Mantel-Haenzel, ajustadas para o tipo de revista. RESULTADOS: Houve crescimento da mediana do n��mero de autores e da propor����o de artigos com mais de quatro autores para todas as revistas, principalmente no ��ltimo tri��nio. As odds ratio para publica����o de artigos com quatro autores ou mais, ajustadas para os tipo de revista, foram: segundo tri��nio: 1,3 (IC95% 1,1;1,4); terceiro tri��nio: 1,5 (IC95% 1,3;1,8); quarto tri��nio: 2,39 (IC95% 2,1;2,8). CONCLUS��ES: Peri��dicos cient��ficos de sa��de coletiva t��m apresentado aumento no n��mero de autores por artigo ao longo dos anos, independentemente da orienta����o editorial.

Aedes aegypti entomological indices in an endemic area for dengue in Sao Paulo State, Brazil

OBJECTIVE: To evaluate the most productive types of properties and containers for Aedes aegypti and the spatial distribution of entomological indices.METHODS: Between December 2006 and February 2007, the vector's immature forms were collected to obtain entomological indices in 9,875 properties in the Jaguare neighborhood of Sao Jose do Rio Preto, SP, Southeastern Brazil. In March and April 2007, a questionnaire about the conditions and characteristics of properties was administered. Logistic regression was used to identify variables associated with the presence of pupae at the properties. Indices calculated per block were combined with a geo-referenced map, and thematic maps of these indices were obtained using statistical interpolation.RESULTS: The properties inspected had the following Ae. aegypti indices: Breteau Index = 18.9, 3.7 larvae and 0.42 pupae per property, 5.2 containers harboring Ae. aegypti per hectare, 100.0 larvae and 11.6 pupae per hectare, and 1.3 larvae and 0.15 pupae per inhabitant. The presence of yards, gardens and animals was associated with the presence of pupae.CONCLUSIONS: Specific types of properties and containers that simultaneously had low frequencies among those positive for the vector and high participation in the productivity of larvae and pupae were not identified. The use of indices including larval and pupal counts does not provide further information beyond that obtained from the traditional Stegomyia indices in locations with characteristics similar to those of S��o Jos�� do Rio Preto. The indices calculated per area were found to be more accurate for the spatial assessment of infestation. The Ae. aegypti infestation levels exhibited extensive spatial variation, indicating that the assessment of infestation in micro areas is needed.

Cumulative mortality of Aedes aegypti larvae treated with compounds

OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs.

Resistance of Aedes aegypti to temephos and adaptive disadvantages

OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Para&#237;ba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos.

Finding Aedes aegypti in a natural breeding site in an urban zone, Sao Paulo, Southeastern Brazil

ABSTRACT This is the description of how nine Aedes aegypti larvae were found in a natural breeding site in the Pinheiros neighborhood, city of Sao Paulo, SP, Southeastern Brazil. The record was conducted in December 2014, during an entomological surveillance program of dengue virus vectors, with an active search of potential breeding sites, either artificial or natural. Finding Ae. aegypti larvae in a tree hole shows this species&#8217; ability to use both artificial and natural environments as breeding sites and habitats, which points towards the importance of maintaining continuous surveillance on this mosquito in all kinds of water-holding containers.

Utiliza����o de amino��cidos no estudo do crescimento do Paracoccidioides brasiliensis: Influ��ncia sobre o dimorfismo

Utilizamos 15 amostras de Paracoccidioides brasiliensis nas formas miceliana (M) e leveduriforme (L), cultivadas em meio m��nimo (MM) e adaptadas ao mesmo meio suplementado com a solu����o de amino��cidos (MMS). Para a realiza����o do estudo auxol��gico das amostras, foram preparadas solu����es complementares das quais foram retirados um amino��cido de cada vez. Nove amostras foram prototr��ficas nas formas M e/ou L e as demais auxotr��ficas para os diferentes amino��cidos e bases nitrogenadas. A heterogeneidade dos resultados apresentados n��o permitiu a caracteriza����o auxol��gica das 15 amostras de P. brasiliensis estudadas. Nenhum dos compostos nitrogenados demonstrou ser essencial para o crescimento ou para a manuten����o da morfog��nese do fungo. Altera����es morfol��gicas (macro e microsc��picas) tamb��m foram observadas, mas somente entre as amostras prototr��ficas, sugerindo a ativa����o de um mecanismo de adapta����o desenvolvido pelo fungo mediante a aus��ncia de substratos nitrogenados no meio de cultura (MM).

An unusual ground larval habitat of Aedes albopictus

Relata-se o encontro de criadouro de Aedes albopictus no solo. Tratou-se de buraco resultante da queda de ��rvore Piptadenia ("angico branco") onde foram coletadas larvas daquele mosquito, juntamente com representantes de Culex declarator, Cx. quinquefasciatus e Culex (Cux.) sp. do Grupo Coronator. O criadouro comportou cerca de 17 litros de ��gua proveniente de chuvas locais. O achado deu-se em mata residual dentro de per��metro urbano da cidade de Pindamo-nhangaba no Vale do Para��ba, Estado de S��o Paulo, Brasil. Discute-se o significado do encontro como prov��vel indicador de ecletismo comportamental e de adapta����o do culic��deo ao ambiente antr��pico.

Frequency, diversity, and productivity study on the Aedes aegypti most preferred containers in the city of Manaus, Amazonas, Brazil

The most preferred containers by Aedes aegypti were studied April and July (rainy and dry periods) in two Manaus neighbourhoods. In all, 2,700 premises and 13,912 containers were examined, most (87%) recorded outdoors. Out of the 13,100 inspected premises, only 1.6% showed to be positive for Aedes aegypti, summing up to 7,916 collected samples. Most frequently found containers outdoors in either neighbourhood regardless of rain or dry period were Bottles flasks and Storage, and indoors, Fixed, Flowerpots, and buckets. Productivity was estimated according to the number of premises and positive containers investigated, showing the actual container groups productivity. Considering both rainy and dry periods outdoors at Pra��a 14 the groups of Tyre, Flask, Bottle, Construction Equipment and Fixed, had the highest averages respectively. Construction Equipment and Flask groups were the most productive in Coroado in April. Flask, Construction Equipment and Storage groups stood out in July.