variola major vs variola major virus

variola major and variola major virus both are nouns.

Word	Noun	Adjective	Verb	Adverb
variola major	Yes	No	No	No
variola major virus	Yes	No	No	No

As nouns, variola major and variola major virus are synonyms defined as:

variola major and variola major virus: a type of smallpox virus that has a fatality rate of up to 25 percent

variola major (noun)	variola major virus (noun)
a type of smallpox virus that has a fatality rate of up to 25 percent	a type of smallpox virus that has a fatality rate of up to 25 percent
a highly contagious viral disease characterized by fever and weakness and skin eruption with pustules that form scabs that slough off leaving scars