title: Chlamydia trachomatis serotype A infections in the Amazon region of Brazil: prevalence, entry and dissemination.
abstract: BACKGROUND
  Chlamydia infection is associated with debilitating human diseases including trachoma, pneumonia, coronary heart disease and urogenital diseases. Serotypes of C. trachomatis show a fair correlation with the group of diseases they cause, and their distribution follows a well-described geographic pattern. Serotype A, a trachoma-associated strain, is known for its limited dissemination in the Middle East and Northern Africa. However, knowledge on the spread of bacteria from the genus Chlamydia as well as the distribution of serotypes in Brazil is quite limited.
  
  
  METHODS
  Blood samples of 1,710 individuals from ten human population groups in the Amazon region of Brazil were examined for antibodies to Chlamydia using indirect immunofluorescence and microimmunofluorescence assays.
  
  
  RESULTS
  The prevalence of antibodies to Chlamydia ranged from 23.9% (Wayana-Apalai) to 90.7% (Awa-Guaja) with a mean prevalence of 50.2%. Seroreactivity was detected to C. pneumoniae and to all serotypes of C. trachomatis tested; furthermore, we report clear evidence of the as-yet-undescribed occurrence of serotype A of C. trachomatis.
  
  
  CONCLUSIONS
  Specific seroreactivity not only accounts for the large extent of dissemination of C. trachomatis in the Amazon region of Brazil but also shows an expanded area of occurrence of serotype A outside the epidemiological settings previously described. Furthermore, these data suggest possible routes of Chlamydia introduction into the Amazon region from the massive human migration that occurred during the 1,700s.
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Marluísa de Oliveira Guimarães
authors.initials: Mde O
authors.lastname: Ishak
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Maurimélia Mesquita
authors.initials: MM
authors.lastname: Costa
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Núbia Caroline Costa de
authors.initials: NC
authors.lastname: Almeida
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Angélica Menezes
authors.initials: AM
authors.lastname: Santiago
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: William Botelho de
authors.initials: WB
authors.lastname: Brito
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Antonio Carlos Rosário
authors.initials: AC
authors.lastname: Vallinoto
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Vânia Nakauth
authors.initials: VN
authors.lastname: Azevedo
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ishak
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D002692:Chlamydia trachomatis / Q000235:genetics* / Q000302:isolation & purification; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D015995:Prevalence; D012703:Serotyping
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G