Revisão sistemática sobre estudos de espacialização da dengue no Brasil

Space-time dispersion of dengue occurrence in epidemic and non-epidemic years in a municipality in the metropolitan region of Belo Horizonte, MG, 2011 to 2017

OBJECTIVE

To analyze the transmission dynamics of dengue, a public health problem in Brazil and the Metropolitan Region of Belo Horizonte (MRBH).

METHODS

The spatiotemporal evolution of the occurrence of dengue in the municipality of Contagem, state of Minas Gerais, a region with high arbovirus transmission, was analyzed. Furthermore, epidemic and non-epidemic periods were analyzed, based on probable cases of dengue. This is an ecological study that used the Notifiable Diseases Information System (SINAN) national database. The analyses were carried out considering the period from epidemiological week (EW) 40 of 2011 to 39 of 2017. Spatial analysis tools (crude and smoothed incidence rate, directional distribution ellipse, global Moran index and local Moran index, and spatial scanning time with definition of epidemiological risk) were used.

RESULTS

The 2012 to 2013 and 2015 to 2016 epidemic cycles presented high incidence rates. The disease was concentrated in more urbanized areas, with a small increase in cases throughout the municipality. Seven statistically significant local clusters and areas with a high rate of cases and accentuated transmission in epidemic cycles were observed throughout the municipality. Spatial autocorrelation of the incidence rate was observed in all periods.

CONCLUSION

The results of the present study highlight a significant and heterogeneous increase in dengue notifications in Contagem over the years, revealing distinct spatial patterns during epidemic and non-epidemic periods. Geoprocessing analysis identified high-risk areas, a piece of knowledge that can optimize the allocation of resources in the prevention and treatment of the disease for that municipality.

Spatial analysis of leishmaniasis in Brazil: a systematized review

The aim of this study was to perform a systematic review of scientific papers that used spatial analysis tools in cases of leishmaniasis, in Brazil. The search for articles was carried out in PubMed, SciELO, Scopus and Web of Science databases. The keywords used in the identification of the articles were Thematic map AND Leishmaniasis, Spatial analysis AND Leishmaniasis, and Geoprocessing AND Leishmaniasis, in English language. A total of 360 articles were found, and 11 of them were analyzed after screening by title and abstract as well as reading of the full articles. The States studied were Sao Paulo, Acre, Maranhao, Piaui, Minas Gerais, Parana and Tocantins. Cutaneous leishmaniasis occurred predominantly in rural areas, with clusters in forest reserve regions or modified forest areas. Conversely, visceral leishmaniasis mainly occurred in peripheral and central urban areas associated with poorer environments and urban infrastructure, including worse sanitation. We conclude that the spatial distribution of leishmaniasis is closely related to the living environment of the risk population. The analyzed articles associated geospatial data with some risk factors for the disease, pointing out the locations where most cases occur, creating a relevant source to define control strategies.

Intra-urbandiferentials in dengue distribution, Cuiabá, 2007-2008

INTRODUCTION

Cuiaba presents a huge number of cases of dengue in the endemic periods as well as in the cyclical epidemics. The aim of the study was to analyze the intra-urban differentials of the incidence in 2007 and 2008 relating them with socio-economical and environmental life conditions.

METHOD

study of ecological approach using secondary data. The characterization of the life conditions was gotten from the Demographic Census (IBGE, 2000) and the epidemiologic data from the Surveillance National System (SINAN). The socio-economical index was based on school level and income of the head of family and overcrowding; the socioambiental index used information about sanitation and proportion of precarious domiciles. The variables were classified in quintis and points were attributed for each one. The score for neighborhood was resultant of the addition of the points for each variable. The neighborhoods had been classified in stratus of risk from the combination of results of the two indexes.

RESULTS

The incidence was lesser in stratus of average and low risk and very high in the stratum of the highest risk but was bigger then expected in the stratum classified at minimum risk indicating dissociation between life conditions and occurrence of the illness.

CONCLUSION

Higher incidences of the dengue fever in Cuiaba in 2007 and 2008 have been observed in places with precarious conditions of sanitation and inhabited by populations with lesser level of income and education level but there is no linear correlation between life conditions and incidence.

Spatial distribution of the risk of dengue fever in southeast Brazil, 2006-2007

BACKGROUND

Many factors have been associated with circulation of the dengue fever virus and vector, although the dynamics of transmission are not yet fully understood. The aim of this work is to estimate the spatial distribution of the risk of dengue fever in an area of continuous dengue occurrence.

METHODS

This is a spatial population-based case-control study that analyzed 538 cases and 727 controls in one district of the municipality of Campinas, São Paulo, Brazil, from 2006-2007, considering socio-demographic, ecological, case severity, and household infestation variables. Information was collected by in-home interviews and inspection of living conditions in and around the homes studied. Cases were classified as mild or severe according to clinical data, and they were compared with controls through a multinomial logistic model. A generalized additive model was used in order to include space in a non-parametric fashion with cubic smoothing splines.

RESULTS

Variables associated with increased incidence of all dengue cases in the multiple binomial regression model were: higher larval density (odds ratio (OR) = 2.3 (95%CI: 2.0-2.7)), reports of mosquito bites during the day (OR = 1.8 (95%CI: 1.4-2.4)), the practice of water storage at home (OR = 2.5 (95%CI: 1.4, 4.3)), low frequency of garbage collection (OR = 2.6 (95%CI: 1.6-4.5)) and lack of basic sanitation (OR = 2.9 (95%CI: 1.8-4.9)). Staying at home during the day was protective against the disease (OR = 0.5 (95%CI: 0.3-0.6)). When cases were analyzed by categories (mild and severe) in the multinomial model, age and number of breeding sites more than 10 were significant only for the occurrence of severe cases (OR = 0.97, (95%CI: 0.96-0.99) and OR = 2.1 (95%CI: 1.2-3.5), respectively. Spatial distribution of risks of mild and severe dengue fever differed from each other in the 2006/2007 epidemic, in the study area.

CONCLUSIONS

Age and presence of more than 10 breeding sites were significant only for severe cases. Other predictors of mild and severe cases were similar in the multiple models. The analyses of multinomial models and spatial distribution maps of dengue fever probabilities suggest an area-specific epidemic with varying clinical and demographic characteristics.

Análise da distribuição espaço-temporal de dengue e da infestação larvária no município de Tupã, Estado de São Paulo

INTRODUÇÃO: O vírus da dengue é transmitido pela picada do mosquito Aedes aegypti e, o atual programa de controle não atinge o objetivo de impedir sua transmissão. Este trabalho objetivou analisar a relação entre a distribuição espaço-temporal de casos de dengue e os indicadores larvários no município de Tupã, de janeiro de 2004 a dezembro de 2007. MÉTODOS: Foram construídos indicadores larvários por quarteirão e totalidade do município. Utilizou-se o método cross-lagged correlation para avaliar a correlação entre casos de dengue e indicadores larvários. Foi utilizado estimador kernel para análise espacial. RESULTADOS: A correlação cruzada defasada entre casos de dengue e indicadores larvários foi significativa. Os mapas do estimador Kernel da positividade de recipientes indicam uma distribuição heterogênea, ao longo do período estudado. Nos dois anos de transmissão, a epidemia ocorreu em diferentes regiões. CONCLUSÕES: Não ficou evidenciada relação espacial entre infestação larvária e ocorrência de dengue. A incorporação de técnicas de geoprocessamento e análise espacial no programa, desde que utilizados imediatamente após a realização das atividades, podem contribuir com as ações de controle, indicando os aglomerados espaciais de maior incidência.