The Human foamy virus (HFV) is a Group IV virus, which is known as spumavirus or spumaretrovirus.
HFV is a member of the retroviridae family, so it has two positive-sense RNA genomes, which means it is diploid. The virus was first identified in 1971 from lymphoblastoid cells in a Kenyan patient with nasopharyngeal carcinoma (on the soft palate of the pharynx of the nasal passage). The isolation and sequencing of a chimpanzee foam virus made it clear that the human virus is a variant of the simian foamy virus, more widespread, and therefore there are no authentic infectious agents in human populations.
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