title: Spatial analysis spotlighting early childhood leprosy transmission in a hyperendemic municipality of the Brazilian Amazon region.
abstract: BACKGROUND
  More than 200,000 new cases of leprosy were reported by 105 countries in 2011. The disease is a public health problem in Brazil, particularly within high-burden pockets in the Amazon region where leprosy is hyperendemic among children.
  
  
  METHODS
  We applied geographic information systems and spatial analysis to determine the spatio-temporal pattern of leprosy cases in a hyperendemic municipality of the Brazilian Amazon region (Castanhal). Moreover, we performed active surveillance to collect clinical, epidemiological and serological data of the household contacts of people affected by leprosy and school children in the general population. The occurrence of subclinical infection and overt disease among the evaluated individuals was correlated with the spatio-temporal pattern of leprosy.
  
  
  RESULTS
  The pattern of leprosy cases showed significant spatio-temporal heterogeneity (p<0.01). Considering 499 mapped cases, we found spatial clusters of high and low detection rates and spatial autocorrelation of individual cases at fine spatio-temporal scales. The relative risk of contracting leprosy in one specific cluster with a high detection rate is almost four times the risk in the areas of low detection rate (RR = 3.86; 95% CI = 2.26-6.59; p<0.0001). Eight new cases were detected among 302 evaluated household contacts: two living in areas of clusters of high detection rate and six in hyperendemic census tracts. Of 188 examined students, 134 (71.3%) lived in hyperendemic areas, 120 (63.8%) were dwelling less than 100 meters of at least one reported leprosy case, 125 (66.5%) showed immunological evidence (positive anti-PGL-I IgM titer) of subclinical infection, and 9 (4.8%) were diagnosed with leprosy (8 within 200 meters of a case living in the same area).
  
  
  CONCLUSIONS
  Spatial analysis provided a better understanding of the high rate of early childhood leprosy transmission in this region. These findings can be applied to guide leprosy control programs to target intervention to high risk areas.
authors: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Marituba, Pará, Brasil ; Universidade Federal do Pará, Campus Castanhal, Pará, Brasil.
authors: Josafá Gonçalves
authors: JG
authors: Barreto
authors: Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America.
authors: Donal
authors: D
authors: Bisanzio
authors: Unidade de Referência Especializada em Dermatologia Sanitária Dr. Marcello Candia, Marituba, Pará, Brasil.
authors: Layana de Souza
authors: Lde S
authors: Guimarães
authors: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America.
authors: John Stewart
authors: JS
authors: Spencer
authors: Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America.
authors: Gonzalo M
authors: GM
authors: Vazquez-Prokopec
authors: Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America.
authors: Uriel
authors: U
authors: Kitron
authors: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Marituba, Pará, Brasil ; Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brasil.
authors: Claudio Guedes
authors: CG
authors: Salgado
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D006801:Humans; D007918:Leprosy / Q000453:epidemiology*; D062206:Spatial Analysis