title: Serological and virological characterization of HIV-1 group O infection in Cameroon.
abstract: OBJECTIVE
  To study the presence of HIV-1 group O infection among HIV-infected people in Cameroon and to further characterize the HIV-1 group O infections.
  
  
  METHODS
  During a 2-year survey (1994-1995), all samples tested positive in screening methods in the National Reference and Public Health Laboratory, Centre Pasteur, Yaoundé, Cameroon were identified as HIV-1 group M, HIV-1 group O or HIV-2 by using a serological algorithm. HIV-1 group M and HIV-1 group O were distinguished on the basis of competitive enzyme-linked immunosorbent assay (ELISA) reactivity against gp41 group M recombinant protein. HIV-1 group O infections were confirmed by using group O-specific V3 synthetic peptides. HIV-1 group O strains were isolated by lymphocyte cocultures, proviral DNA was amplified with specific primers, and sequencing was performed on the C2V3 and gag regions.
  
  
  RESULTS
  Of the 8,331 screened samples, 3,193 were HIV-reactive, 2,376 (74%) of which were considered to belong to group M. The 817 (26%) that had reacted poorly or not at all against group M gp41 were further characterized: 10 were confirmed as HIV-2 and 82 as HIV-1 group O, the others being indeterminate (n = 285) or negative (n = 440). The frequency of group O relative to group M ranged from 1% in Far North province to 6.3% in the capital. There was no difference in sex, age or frequency of clinical manifestations between group M and group O infections. Group O infection was confirmed in a subset of cases by polymerase chain reaction (n = 14), with perfect concordance. Sequencing and phylogenetic analyses confirmed the high variability inside group O.
  
  
  CONCLUSIONS
  Group O and group M epidemiological patterns are known to be similar so the reason for the lower prevalence of group O remains to be found. The wide distribution of group O infection in all Cameroonian provinces underlines the importance of further characterizing the epidemic spread and diffusion of this group.
authors.affiliation: Centre Pasteur du Cameroun, National Public Health and Reference Laboratory Yaoundé, Cameroun.
authors.forename: P
authors.initials: P
authors.lastname: Mauclère
authors.forename: I
authors.initials: I
authors.lastname: Loussert-Ajaka
authors.forename: F
authors.initials: F
authors.lastname: Damond
authors.forename: P
authors.initials: P
authors.lastname: Fagot
authors.forename: S
authors.initials: S
authors.lastname: Souquières
authors.forename: M
authors.initials: M
authors.lastname: Monny Lobe
authors.forename: F X
authors.initials: FX
authors.lastname: Mbopi Keou
authors.forename: F
authors.initials: F
authors.lastname: Barré-Sinoussi
authors.forename: S
authors.initials: S
authors.lastname: Saragosti
authors.forename: F
authors.initials: F
authors.lastname: Brun-Vézinet
authors.forename: F
authors.initials: F
authors.lastname: Simon
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002163:Cameroon; D018920:Coculture Techniques; D004279:DNA, Viral / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D015750:Genes, gag; D015483:HIV Antibodies / Q000097:blood; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D015498:HIV-2 / Q000145:classification / Q000276:immunology / Q000302:isolation & purification; D007118:Immunoassay; D007963:Leukocytes, Mononuclear; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D004279:DNA, Viral; D015483:HIV Antibodies