Spatial Analysis of Dengue Seroprevalence and Modeling of Transmission Risk Factors in a Dengue Hyperendemic City of Venezuela

PLoS Negl Trop Dis. 2017 Jan 23;11(1):e0005317. doi: 10.1371/journal.pntd.0005317. eCollection 2017 Jan.

Abstract

Background: Dengue virus (DENV) transmission is spatially heterogeneous. Hence, to stratify dengue prevalence in space may be an efficacious strategy to target surveillance and control efforts in a cost-effective manner particularly in Venezuela where dengue is hyperendemic and public health resources are scarce. Here, we determine hot spots of dengue seroprevalence and the risk factors associated with these clusters using local spatial statistics and a regression modeling approach.

Methodology/principal findings: From August 2010 to January 2011, a community-based cross-sectional study of 2012 individuals in 840 households was performed in high incidence neighborhoods of a dengue hyperendemic city in Venezuela. Local spatial statistics conducted at household- and block-level identified clusters of recent dengue seroprevalence (39 hot spot households and 9 hot spot blocks) in all neighborhoods. However, no clusters were found for past dengue seroprevalence. Clustering of infection was detected at a very small scale (20-110m) suggesting a high disease focal aggregation. Factors associated with living in a hot spot household were occupation (being a domestic worker/housewife (P = 0.002), lower socio-economic status (living in a shack (P<0.001), sharing a household with <7 people (P = 0.004), promoting potential vector breeding sites (storing water in containers (P = 0.024), having litter outdoors (P = 0.002) and mosquito preventive measures (such as using repellent, P = 0.011). Similarly, low socio-economic status (living in crowded conditions, P<0.001), having an occupation of domestic worker/housewife (P = 0.012) and not using certain preventive measures against mosquitoes (P<0.05) were directly associated with living in a hot spot block.

Conclusions/significance: Our findings contribute to a better comprehension of the spatial dynamics of dengue by assessing the relationship between disease clusters and their risk factors. These results can inform health authorities in the design of surveillance and control activities. Focalizing dengue control measures during epidemic and inter-epidemic periods to disease high risk zones at household and neighborhood-level may significantly reduce virus transmission in comparison to random interventions.

MeSH terms

  • Adolescent
  • Adult
  • Aedes / virology
  • Animals
  • Antibodies, Viral / blood
  • Child
  • Cities / statistics & numerical data
  • Cross-Sectional Studies
  • Dengue / blood
  • Dengue / epidemiology*
  • Dengue / transmission*
  • Dengue / virology
  • Dengue Virus / immunology
  • Dengue Virus / physiology
  • Female
  • Humans
  • Insect Vectors / virology
  • Male
  • Risk Factors
  • Seroepidemiologic Studies
  • Spatial Analysis
  • Venezuela / epidemiology
  • Young Adult

Substances

  • Antibodies, Viral

Grants and funding

This work was supported by the Fondo Nacional de Ciencia y Tecnología e Innovación (FONACIT), grant 201100129, 201300201; and by the Coordinación de Aplicación de Fondos e Incentivos para el Desarrollo de Planes de Ciencia, Tecnología e Innovación, Organic Law of Science, Technology and Innovation (LOCTI), certification No DGCAFIDCTI/204-214-10, of the Venezuelan Ministry of Science, Technology and Innovation, Venezuela; and by the University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands. MFVG and EFL received a grant from the UMCG, University of Groningen, Groningen, The Netherlands. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.