title: Spatial Distribution of Dengue in a Brazilian Urban Slum Setting: Role of Socioeconomic Gradient in Disease Risk.
abstract: BACKGROUND
  Few studies of dengue have shown group-level associations between demographic, socioeconomic, or geographic characteristics and the spatial distribution of dengue within small urban areas. This study aimed to examine whether specific characteristics of an urban slum community were associated with the risk of dengue disease.
  
  
  RESULTS
  From 01/2009 to 12/2010, we conducted enhanced, community-based surveillance in the only public emergency unit in a slum in Salvador, Brazil to identify acute febrile illness (AFI) patients with laboratory evidence of dengue infection. Patient households were geocoded within census tracts (CTs). Demographic, socioeconomic, and geographical data were obtained from the 2010 national census. Associations between CTs characteristics and the spatial risk of both dengue and non-dengue AFI were assessed by Poisson log-normal and conditional auto-regressive models (CAR). We identified 651 (22.0%) dengue cases among 2,962 AFI patients. Estimated risk of symptomatic dengue was 21.3 and 70.2 cases per 10,000 inhabitants in 2009 and 2010, respectively. All the four dengue serotypes were identified, but DENV2 predominated (DENV1: 8.1%; DENV2: 90.7%; DENV3: 0.4%; DENV4: 0.8%). Multivariable CAR regression analysis showed increased dengue risk in CTs with poorer inhabitants (RR: 1.02 for each percent increase in the frequency of families earning ≤1 times the minimum wage; 95% CI: 1.01-1.04), and decreased risk in CTs located farther from the health unit (RR: 0.87 for each 100 meter increase; 95% CI: 0.80-0.94). The same CTs characteristics were also associated with non-dengue AFI risk.
  
  
  CONCLUSIONS
  This study highlights the large burden of symptomatic dengue on individuals living in urban slums in Brazil. Lower neighborhood socioeconomic status was independently associated with increased risk of dengue, indicating that within slum communities with high levels of absolute poverty, factors associated with the social gradient influence dengue transmission. In addition, poor geographic access to health services may be a barrier to identifying both dengue and non-dengue AFI cases. Therefore, further spatial studies should account for this potential source of bias.
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors.forename: Mariana
authors.initials: M
authors.lastname: Kikuti
authors.affiliation: Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Geraldo M
authors.initials: GM
authors.lastname: Cunha
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors.forename: Igor A D
authors.initials: IA
authors.lastname: Paploski
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Amelia M
authors.initials: AM
authors.lastname: Kasper
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Monaise M O
authors.initials: MM
authors.lastname: Silva
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Aline S
authors.initials: AS
authors.lastname: Tavares
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Jaqueline S
authors.initials: JS
authors.lastname: Cruz
authors.affiliation: Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors.forename: Tássia L
authors.initials: TL
authors.lastname: Queiroz
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Moreno S
authors.initials: MS
authors.lastname: Rodrigues
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Perla M
authors.initials: PM
authors.lastname: Santana
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Helena C A V
authors.initials: HC
authors.lastname: Lima
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Juan
authors.initials: J
authors.lastname: Calcagno
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: Daniele
authors.initials: D
authors.lastname: Takahashi
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors.forename: André H O
authors.initials: AH
authors.lastname: Gonçalves
authors.affiliation: Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: Josélio M G
authors.initials: JM
authors.lastname: Araújo
authors.affiliation: Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Kristine
authors.initials: K
authors.lastname: Gauthier
authors.affiliation: Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Diuk-Wasser
authors.affiliation: Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Uriel
authors.initials: U
authors.lastname: Kitron
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America; Faculdade de Medicina, Universidade Federal da Bahia, Salvador, Bahia, Brazil.
authors.forename: Mitermayer G
authors.initials: MG
authors.lastname: Reis
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil; Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil; Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Guilherme S
authors.initials: GS
authors.lastname: Ribeiro
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003715:Dengue / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D011204:Poverty Areas; D012307:Risk Factors; D012959:Socioeconomic Factors; D055815:Young Adult