Human herpesvirus 8 in Brazilian Amerindians: A hyperendemic population with a new subtype

Human herpesvirus 8 (HHV-8) epidemiology in Brazilian Amerindians was studi ed. Use of an immunofluorescence (IFA) test for latent antibody demonstrate d that the prevalence of HHV-8 in 781 Amerindians of diverse tribes (overal l, 53% prevalence) was not related to language group or sex but rather incr eased gradually from 41% in children <10 years of age to 65% in adults grea ter than or equal to 30 years of age. In IFA-positive subjects, HHV-8 DNA w as detected in 3 (16%) of 19 mononuclear cell samples from peripheral blood and in 1 of 16 saliva samples, The sequences of conserved ORF22 and K6 gen es were typical of HHV-8, but the variable KI gene sequences were only 70%- 75% identical to other known HHV-8 strains. Thus, a new HHV-8 subtype, E, i s hyperendemic in Brazilian Amerindians, although Kaposi's sarcoma has not been reported. Transmission is probably oral rather than sexual. The limite d genetic pool in isolated groups may permit more frequent transmission of a virus with a low prevalence in heterogeneous populations.