A virus genus encompassing a poorly characterized group of retroviruses that cause vacuolation (foaming) of cultured cells; usually cause persistent but silent infections in their natural hosts and no diseases caused by these agents have been identified.
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Spu·ma·vi·rus (spuґmə-vi″rəs) [L. spuma foam + virus] the foamy viruses, a genus of nonpathogenic viruses of the family Retroviridae, having characteristic virion morphology with a central condensed core and prominent surface spikes. They are named for the foamy appearance of infected cells in cultures, caused by extensive vacuolation. Capsid assembly occurs in the cytoplasm prior to budding through the plasma membrane. Organisms can induce persistent, asymptomatic infection in numerous different mammals.Medical dictionary. 2011.