HTLV-I in Australia and Oceania: long-term resident or recent immigrant?

Human T-cell lymphotropic virus type I (HTLV-I) has a worldwide distribution; infection rates of up to 14% have been found in Aboriginal communities, but there is little evidence of typical HTLV-I-associated disease. The strains among Australian Aboriginals and Melanesians are more closely related to each other at the molecular level than to strains from Africa, Japan and the Caribbean basin. The clinical significance of these Oceanic strains of HTLV-I in endemically infected communities is unclear.