title: Prevalence and risk behaviour for human immunodeficiency virus 1 infection in Marajó Island, Northern Brazil.
abstract: BACKGROUND
  Human immunodeficiency virus 1 (HIV-1) infection is a global public health problem, but, so far, there is no published information regarding the epidemiology of HIV-1 in Marajó Archipelago (Pará, Brazil).
  
  
  OBJECTIVE
  The present study reports the occurrence of infection by HIV-1 in four municipalities of the Marajó Island, Pará, Brazil.
  
  
  METHODS
  A total of 1877 samples were collected from volunteer blood donors (1296 women and 551 men) living in the municipalities of Anajás, Chaves, Portel and São Sebastião da Boa Vista. Information about risk behaviour assessment was obtained from a questionnaire. Plasma samples were tested for the presence of anti-HIV antibodies using serological tests. The infection was confirmed by nucleic acid amplification assays.
  
  
  RESULTS
  Twelve samples were seropositive for HIV by ELISA. Western blot analysis showed four positive samples, eight indeterminate patterns and one found to be negative. Molecular analysis revealed three positive samples. Risk factors for HIV-1 infection included absence of condoms during sexual intercourse (41.3%, São Sebastião da Boa Vista), use of illicit drugs (5.8%, Anajás) and early initiation of sexual activities, from 10-15 years (30.7%).
  
  
  CONCLUSIONS
  Although the study indicates a low HIV-1 prevalence in Marajó Island, some factors may increase the risk for HIV-1 and these include early sexual initiation, unprotected sexual intercourse and the use of illicit drugs.
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Antonio C R
authors.initials: AC
authors.lastname: Vallinoto
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Samantha
authors.initials: S
authors.lastname: Aguiar
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Keyla G
authors.initials: KG
authors.lastname: Sá
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Felipe Bonfim
authors.initials: FB
authors.lastname: Freitas
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Glenda
authors.initials: G
authors.lastname: Ferreira
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Sandra Souza
authors.initials: SS
authors.lastname: Lima
authors.affiliation: b Fundação de Hematologia e Hemoterapia do Pará (HEMOPA) , Belém , Pará , Brazil.
authors.forename: Renata Bezerra
authors.initials: RB
authors.lastname: Hermes
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Luiz Fernando Almeida
authors.initials: LF
authors.lastname: Machado
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Izaura
authors.initials: I
authors.lastname: Cayres-Vallinoto
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Marluísa
authors.initials: M
authors.lastname: Ishak
authors.affiliation: a Universidade Federal do Pará, Instituto de Ciências Biológicas, Laboratório de Virologia, Cidade Universitária , Belém , Pará , Brazil ;
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ishak
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D003710:Demography; D005260:Female; D005843:Geography; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology* / Q000235:genetics / Q000821:virology*; D006679:HIV Seropositivity / Q000097:blood; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D062312:Islands; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012309:Risk-Taking; D055815:Young Adult
keywords: HIV-1; Marajó Island; epidemiology; prevalence