Scientific Nomenclature says that:
Italics are used for bacterial and viral taxa at the level of family and below. All bacterial and many viral genes are italicized. Serovars of Salmonella enterica are not italicized
When a sentence with a viral name is in an italicized environment (in a quote, in a reference list), should it be written in italics or roman? In
\emph command provides such a relative "emphasis", with respect to the surrounding sentence.