title: Spatial epidemiology and serologic cohorts increase the early detection of leprosy.
abstract: BACKGROUND
  Leprosy remains an important public health problem in some specific high-burden pockets areas, including the Brazilian Amazon region, where it is hyperendemic among children.
  
  
  METHODS
  We selected two elementary public schools located in areas most at risk (cluster of leprosy or hyperendemic census tract) to clinically evaluate their students. We also followed anti-PGL-I seropositive and seronegative individuals and households for 2 years to compare the incidence of leprosy in both groups.
  
  
  RESULTS
  Leprosy was detected in 11 (8.2 %) of 134 school children in high risk areas. The difference in the prevalence was statistically significant (p < .05) compared to our previous findings in randomly selected schools (63/1592; 3.9 %). The 2-year follow-up results showed that 22.3 and 9.4 % of seropositive and seronegative individuals, respectively, developed leprosy (p = .027). The odds of developing overt disease in seropositive people were 2.7 times that of negative people (p < .01), indicating that a follow-up of 10 seropositives has a >90 % probability to detect at least one new case in 2 years. The odds of clinical leprosy were also higher in "positive houses" compared to "negative houses" (p < .05), indicating that a follow-up of ten people living in households with at least one seropositive dweller have a 85 % probability to detect at least one new case in 2 years.
  
  
  CONCLUSIONS
  Targeted screening involving school-based surveillance planned using results obtained by spatial analysis and targeted household and individual continuous surveillance based on serologic data should be applied to increase the early detection of new leprosy cases.
authors.affiliation: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Av. João Paulo II, 113. Bairro Dom Aristides, Marituba, CEP: 67200-000, , Pará, Brazil. jbarreto@ufpa.br.|Universidade Federal do Pará, Campus Castanhal, Marituba, Pará, Brazil. jbarreto@ufpa.br.
authors.forename: Josafá Gonçalves
authors.initials: JG
authors.lastname: Barreto
authors.affiliation: Department of Environmental Sciences, Emory University, Atlanta, GA, USA. donal.bisanzio@gmail.com.
authors.forename: Donal
authors.initials: D
authors.lastname: Bisanzio
authors.affiliation: Divison of Dermatology of Internal Medicine Department of Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. mandrey@fmrp.usp.br.
authors.forename: Marco Andrey Cipriani
authors.initials: MA
authors.lastname: Frade
authors.affiliation: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Av. João Paulo II, 113. Bairro Dom Aristides, Marituba, CEP: 67200-000, , Pará, Brazil. taniafarma@gmail.com.
authors.forename: Tania Mara Pires
authors.initials: TM
authors.lastname: Moraes
authors.affiliation: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Av. João Paulo II, 113. Bairro Dom Aristides, Marituba, CEP: 67200-000, , Pará, Brazil. angelik.gobbo@gmail.com.
authors.forename: Angélica Rita
authors.initials: AR
authors.lastname: Gobbo
authors.affiliation: Unidade de Referência Especializada em Dermatologia Sanitária Dr. Marcello Candia, Marituba, Pará, Brazil. layanaguimaraes@hotmail.com.
authors.forename: Layana
authors.initials: L
authors.lastname: de Souza Guimarães
authors.affiliation: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Av. João Paulo II, 113. Bairro Dom Aristides, Marituba, CEP: 67200-000, , Pará, Brazil. moises@ufpa.br.|Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil. moises@ufpa.br.
authors.forename: Moisés Batista
authors.initials: MB
authors.lastname: da Silva
authors.affiliation: Department of Environmental Sciences, Emory University, Atlanta, GA, USA. gmvazqu@emory.edu.
authors.forename: Gonzalo M
authors.initials: GM
authors.lastname: Vazquez-Prokopec
authors.affiliation: Department of Microbiology, Immunology and Pathology, Mycobacteria Research Laboratories, Colorado State University, Fort Collins, CO, USA. John.Spencer@colostate.edu.
authors.forename: John Stewart
authors.initials: JS
authors.lastname: Spencer
authors.affiliation: Department of Environmental Sciences, Emory University, Atlanta, GA, USA. ukitron@emory.edu.
authors.forename: Uriel
authors.initials: U
authors.lastname: Kitron
authors.affiliation: Laboratório de Dermato-Imunologia UEPA/UFPA/Marcello Candia, Av. João Paulo II, 113. Bairro Dom Aristides, Marituba, CEP: 67200-000, , Pará, Brazil. csalgado@ufpa.br.|Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil. csalgado@ufpa.br.
authors.forename: Claudio Guedes
authors.initials: CG
authors.lastname: Salgado
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D042241:Early Diagnosis; D005191:Family Characteristics; D005260:Female; D005500:Follow-Up Studies; D006017:Glycolipids / Q000276:immunology; D006801:Humans; D007918:Leprosy / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D012574:Schools; D013334:Students; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D006017:Glycolipids; C045169:phenolic glycolipid I, Mycobacterium leprae