[Spatial analysis of dengue transmission in a medium-sized city in Brazil].

Departamento de Epidemiologia e Saúde Coletiva, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP, Brasil.
Revista de Saúde Pública (Impact Factor: 1.22). 07/2005; 39(3):444-51.
Source: PubMed

ABSTRACT To perform spatial analysis on dengue transmission in a medium-sized city in the interior of the State of São Paulo, Brazil, covering the period from September 1990 to August 2002.
Autochthonous cases with confirmation by laboratory tests were utilized. Population data on the city of São José do Rio Preto were obtained from the Brazilian Institute for Geography and Statistics and the municipal authorities. The cases were georeferenced according to street addresses and clustered according to the 432 census tracts in the municipality, thus resulting in thematic maps.
A rising trend in annual incidence was noted, with a peak in 2000/2001. From 1990 to 1994 the length of the transmission period reached a maximum of five months per year. This period increased in length over subsequent years. In the final year investigated, transmission occurred in all twelve months, without interruptions. Analysis of the period of highest incidence showed that the transmission did not occur uniformly. While 29% of the tracts registered incidences of less than 1,000 cases per 100,000 inhabitants, 5% of them had more than 5,000 cases.
A process of increasing endemicity was observed, with transmission throughout the year, without the need for virus introducers. The endemic characteristic of the transmission and the differentiated occurrence according to areas need to be taken into account when developing strategies for dengue control.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The service currently uses for monitoring the Dengue’s vectors, two indexes, the Breteau’s Index and the building infestation Index, both basing in the larval stage. These indexes do not propitiate information to identify the strategical containers breeding, keys to Ae. aegypti surveillance, because they indicates only the larvae forms presence and not the productivity in these containers. This research objectified to study the spatial distribution of the Ae. aegypti’s containers breeding and the importance of these in the maintenance of their vector’s population in urban conglomerates with high infestation’s density. The indexes gotten in 2004 had been analyzed in two scales: wards and blocks. Later, in the period of December/2004 to April/2005, we proceeded the biweekly collection of all immature mosquitoes forms in containers breeding in blocks with larvae’s high density, identified in the spatial analysis. The container’s productivity in blocks was analyzed using the Kernel’s method, being also verified the potentials of the vector’s adult females production in these, according for the characteristics of them. The joint participation of containers in the adult specimen production was also evaluated. The Kernel’s analysis identified strategical urban conglomerates with high infestation’s densities, demonstrating to be an efficient method to Ae. aegypti surveillance. The containers with volumes between 1 and 1,000 liters had been more productive, also playing the function of feeders for the secondary containers breeding situated in the neighborhood of them. The containers with volume less than 50ml had not demonstrated capacity to produce adult forms. The containers with volumes between 50 and 100ml and that with volume above 5,000 liters had been much less productive not having importance for the surveillance. The methodology used in this research can easily be incorporated by the service, being necessary to adopt the use of the geo processing in the routine.
    03/2006, Degree: Master, Supervisor: Reinaldo Souza Santos
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Culex flavivirus (CxFV) was first isolated in 2007 from Culex pipiens in Japan and then identified in several other countries. Characterization of the CxFV showed that all strains are related to the cell fusing agent virus. In this manuscript we report the first identification of CxFV in South America. Material and Methods: We have collected Culex sp. mosquitoes using BG-Sentinel traps and manual aspirators. They were pooled according to genus, species, sex and location. Viral RNA was extracted and multiplex nested PCR was performed to test the presence of Flavivirus. The positive samples were isolated in C6/36 cells and sequenced for phylogenetic analyses. Results: 265 female Culex mosquitoes pooled in 83 pools were tested with specific CxFV, Saint Louis encephalitis virus (SLEV) and West Nile virus (WNV) primers. Our sequence data indicated maximum sequence similarity of 97% with CxFV. Discussion: In this study we report the circulation of CxFV in an urban setting where SLEV had previously caused an outbreak. In terms of public health, this is an important finding due to the assumption that the previous exposition of mosquitoes to CxFV might lessen the susceptibility of these mosquitoes to other flaviviruses.
    Intervirology 08/2012; 55(6):475-83. DOI:10.1159/000337166 · 1.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Global dengue virus spread in tropical and sub-tropical regions has become a major international public health concern. It is evident that DENV genetic diversity plays a significant role in the immunopathology of the disease and that the identification of polymorphisms associated with adaptive responses is important for vaccine development. The investigation of naturally occurring genomic variants may play an important role in the comprehension of different adaptive strategies used by these mutants to evade the human immune system. In order to elucidate this role we sequenced the complete polyprotein-coding region of thirty-three DENV-3 isolates to characterize variants circulating under high endemicity in the city of Sao Jose de Rio Preto, Brazil, during the onset of the 2006-07 epidemic. By inferring the evolutionary history on a local-scale and estimating rates of synonymous (dS) and nonsynonimous (dN) substitutions, we have documented at least two different introductions of DENV-3 into the city and detected 10 polymorphic codon sites under significant positive selection (dN/dS > 1) and 8 under significant purifying selection (dN/dS < 1). We found several polymorphic amino acid coding sites in the envelope (15), NS1 (17), NS2A ( 11), and NS5 (24) genes, which suggests that these genes may be experiencing relatively recent adaptive changes. Furthermore, some polymorphisms correlated with changes in the immunogenicity of several epitopes. Our study highlights the existence of significant and informative DENV variability at the spatio-temporal scale of an urban outbreak.
    PLoS ONE 05/2013; PLoS ONE 8(5): e63496. doi:10.1371/journal.pone.0063496. DOI:10.1371/journal.pone.0063496 · 3.53 Impact Factor


1 Download
Available from