Background: KSHV/HHV-8 is the etiological agent of Kaposi's sarcoma, primary effusion lymphoma and most multicentric Castleman's disease cases. KSHV exhibits a high genetic variability comprising five genotypes (A-E). Few data are yet available concerning the situation of KSHV, its genetic variability and the associated diseases in Melanesia.
Objectives: We performed a study on 626 natives Melanesians from New Caledonia and Vanikoro Island to evaluate KSHV seroprevalence and characterize molecularly the viral strains.
Study design: Plasma from 343 males and 283 females (age range: 15-86 years, mean age: 60) were tested for KSHV latent antibodies by an immunofluorescence assay (IFA) using BC-3 cells. DNAs extracted from peripheral blood buffy-coat of KSHV seropositive individuals were amplified to obtain a 737-bp fragment of the ORF-K1 gene. Phylogenetic analyses were then performed.
Results: Among 626 samples, 148 were IFA positive (dilution≥1:80). The overall seroprevalence was 23.6% (25.2% in New Caledonia, 17.5% in Vanikoro). Fifteen (8 men and 7 women, mean age 69 years) out of 148 DNA samples were found PCR positive. All ORF-K1 sequences belonged to KSHV genotype D. A geographic clustering according to the island of origin of KSHV infected persons was clearly observed with sequences from New Caledonia clustering with most Vanuatu strains.
Conclusions: New Caledonia and Vanikoro are endemic for KSHV with a high diversity of genotype D variants. These strains were probably introduced into New Caledonia during multiple waves of migrations of Melanesian and Polynesian individuals that have colonized this archipelago.
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