title: Prevalence of human papillomavirus infection and phylogenetic analysis of HPV-16 E6 variants among infected women from Northern Brazil.
abstract: BACKGROUND
  The main cause of cervical cancer in the world is high risks human papillomavirus infection (mainly represented by HPV-16 and HPV-18), that are associated to the development of malign transformation of the epithelium. HPV prevalence exhibits a wide geographical variability and HPV-16 variants have been related to an increased risk of developing cervical intraepithelial lesion. The aim of this study was to describe DNA-HPV prevalence and HPV-16 variants among a women population from Northern Brazil.
  
  
  METHODS
  One hundred and forty three women, during routine cervical cancer screening, at Juruti Project, fulfilled an epidemiological inquiry and were screened through a molecular HPV test. HPV-16 variants were determined by sequencing the HPV-16 E6 open reading frame.
  
  
  RESULTS
  Forty two samples were considered HPV positive (29.4%). None of those had abnormal cytology results. HPV prevalence varied between different age groups (Z(U) = 14.62; p = <0.0001) and high-risk HPVs were more frequent among younger ages. The most prevalent type was HPV-16 (14%) and it variants were classified, predominantly, as European (87.5%).
  
  
  CONCLUSIONS
  HPV prevalence in our population was higher than described by others and the most prevalent HPV types were high-risk HPVs. The European HPV-16 variant was the most prevalent among HPV-16 positive samples. Our study reinforces the fact that women with normal cytology and a positive molecular test for high-risk HPVs should be submitted to continuous follow up, in order to verify persistence of infection, promoting an early diagnosis of cervical cancer and/or its precursors.
authors.affiliation: Laboratório de Papilomavírus, Seção de virologia, Instituto Evandro Chagas, Rodovia BR 316 km 07, Ananindeua, Pará, Brazil.
authors.forename: Bruna Pedroso
authors.initials: BP
authors.lastname: Tamegão-Lopes
authors.affiliation: Laboratório de Papilomavírus, Seção de virologia, Instituto Evandro Chagas, Rodovia BR 316 km 07, Ananindeua, Pará, Brazil.
authors.forename: Edivaldo Costa
authors.initials: EC
authors.lastname: Sousa-Júnior
authors.affiliation: Instituto Nacional de Câncer (INCA), Clinical Research Coordination, Rua André Cavalcanti, 37, 20231-050 Rio de Janeiro, RJ, Brazil.
authors.forename: Fabio
authors.initials: F
authors.lastname: Passetti
authors.affiliation: Instituto Nacional de Câncer (INCA), Clinical Research Coordination, Rua André Cavalcanti, 37, 20231-050 Rio de Janeiro, RJ, Brazil.
authors.forename: Carlos Gil
authors.initials: CG
authors.lastname: Ferreira
authors.affiliation: Laboratório de Papilomavírus, Seção de virologia, Instituto Evandro Chagas, Rodovia BR 316 km 07, Ananindeua, Pará, Brazil.
authors.forename: Wyller Alencar
authors.initials: WA
authors.lastname: de Mello
authors.affiliation: Laboratório de Papilomavírus, Seção de virologia, Instituto Evandro Chagas, Rodovia BR 316 km 07, Ananindeua, Pará, Brazil.
authors.forename: Rodrigo Vellasco
authors.initials: RV
authors.lastname: Duarte Silvestre
keywords: HPV; HPV-16; Prevalence; Variants