Increasing seroprevalence of Human herpesvirus 8 (HHV-8) with age confirms HHV-8 endemicity in Amazon Amerindians from Brazil

1 Departments of Clinical Pathology and Internal Medicine, School of Medical Sciences/State University of Campinas (UNICAMP), Brazil 2 Gonçalo Moniz Research Center/Fiocruz, 121 rua Waldemar Falcão, 40295-001 Salvador, BA, Brazil 3 Immunology Section, Adolfo Lutz Institute, São Paulo, Brazil 4 Bahiana Medical School, Bahiana Foundation for the Development of Sciences, Salvador, Brazil Correspondence B. Galvão-Castro bgalvao{at}cpqgm.fiocruz.br Human herpesvirus 8 (HHV-8) seroprevalences were determined in two isolated Amazon Amerindian tribes, according to age, gender and familial aggregation. Plasma and serum samples obtained from 982 Amazon Amerindians (664 Tiriyó and 318 Waiampi) were tested for antibodies against lytic and latent HHV-8 antigens by using ‘in-house’ immunofluorescence assays. Overall, HHV-8 seroprevalence was 56·8 % (57·4 % in the Tiriyó tribe and 55·7 % in the Waiampi tribe). Seroprevalence was independent of gender and increased linearly with age: it was 35·0 % among children aged 2–9 years, 51·4 % in adolescents (10–19 years), 72·9 % in adults and 82·3 % in adults aged >50 years. Interestingly, 44·4 % of children under 2 years of age were HHV-8-seropositive. No significant differences in seroprevalence between tribes and age groups were detected. It is concluded that HHV-8 is hyperendemic in Brazilian Amazon Amerindians, with vertical and horizontal transmission during childhood, familial transmission and sexual contact in adulthood contributing to this high prevalence in these isolated populations.