Dynamics of dengue virus circulation: a silent epidemic in a complex urban area.

Serotypes of dengue DEN-1 and DEN-2 have been reported in much of Brazil over the last 15 years, and DEN-3 serotype was only recently detected. This prospective study was conducted in Salvador, a large city in north-east Brazil, where two epidemics were previously recorded (DEN-1 and DEN-2). We obtained the seroprevalence and 1-year incidence of dengue infections in the population of 30 sampling areas of Salvador and analysed the relationship between intensity of viral circulation, standard of living and vector density. High seroprevalence (68.7%) and annual incidence (70.6%) of infection for one or both circulating serotypes (DEN-1 and DEN-2) were found. High rates of transmission were observed in all studied areas, from the highest to the lowest socio-economic status. The mean PI (Premise Index) for Aedes aegypti was 7.4% (range 0.27-25.6%). Even in the areas with the lowest PI (</=3%) the observed seroincidence was 54.6%. These findings highlighted the existence of a silent epidemic during a period perceived by the Health Services as of low endemicity, indicating the strength and speed of dengue transmission in the city of Salvador

Revisão sistemática sobre estudos de espacialização da dengue no Brasil Systematic review of spatial analysis studies on dengue in Brazil

O presente estudo objetivou realizar uma revisão sistemática sobre estudos de geoprocessamento do vetor da dengue e da doença no Brasil. A busca dos trabalhos foi realizada nas bases de dados Pubmed, Bireme e Scielo. A seleção foi realizada por critérios de inclusão, sendo estes: artigos originais sobre dengue e emprego de técnicas de geoprocessamento, publicados em inglês ou português de 1998 a 2007; trabalhos de finalização de curso; e trabalhos apresentados em congresso. Trabalhos que avaliaram essa doença em outros países foram excluídos. As palavras-chaves utilizadas na identificação dos artigos foram: "distribuição espacial e dengue", "dengue e geoprocessamento", "análise espacial e dengue", "Sistema de Informações Geográficas e dengue" e suas traduções para língua inglesa. Na base de busca do Scielo foram encontrados 15 artigos, dos quais selecionou-se 8; na Pubmed 11 trabalhos foram identificados, dos quais utilizou-se 3; e na Bireme, 20 trabalhos, dos quais selecionou-se 2. A revisão realizada permitiu analisar 7 estudos de espacialização dos casos de dengue, 5 trabalhos com vetores da dengue e um estudo que avaliou os casos e os vetores, simultaneamente. Foi freqüente a não-utilização de técnicas de geoprocessamento. Aspectos sociais foram freqüentemente associados à distribuição espacial da dengue. Desta forma, concluiu-se que os estudos de espacialização da dengue no Brasil, especialmente aqueles que avaliam os seus vetores, subutilizam as ferramentas do geoprocessamento. Os aspectos socioeconômicos são importantes para o entendimento da distribuição espacial da dengue.<br>The present study aimed to carry out a systematic review of geoprocessing studies on the dengue vector and the disease in Brazil. The search was conducted in the Pubmed and Bireme databases and in Scielo virtual library. The selection was carried out using inclusion criteria, such as: original articles on dengue and the use of geoprocessing techniques, published in English or in Portuguese, from 1998 to 2007; final course works; and studies presented at congresses. Studies which evaluated the disease in other countries were excluded. The key words used were "spatial distribution and dengue", "dengue and geoprocessing", "spatial analysis and dengue", "geographic information system and dengue" and their translations into Portuguese. In the Scielo database search, 15 articles were found, from which 8 were selected; in Pubmed, 11 articles were identified and 3 were selected; and in Bireme 20 articles were found, from which 2 were selected. The present review allowed the analysis of 7 studies on the spatial pattern of dengue cases, 5 studies on dengue vectors and one study that evaluated dengue cases and vectors, simultaneously. The non-utilization of geoprocessing techniques was frequent. Social aspects were frequently associated with the spatial distribution of dengue. The study concludes that spatial analyses of dengue in Brazil, especially those that evaluated vectors, used geoprocessing tools poorly. Socioeconomic aspects are important to understand the spatial distribution of dengue