Italicize family, genus, species, and variety or subspecies. Begin family and genus with a capital letter. Kingdom, phylum, class, order, and suborder begin with a capital letter but are not italicized. If a generic plural for an organism exists (see Dorland’s), it is neither capitalized nor italicized.talicize species, genus, and family of a virus when used in a taxonomic sense. Note however, that it is fine to not mention taxonomy of a virus, especially one like dengue or polio that is well known.