Heather Nova??? It is to laugh.

She almost certainly got the phrase from Richard Brodie's book, Virus of the Mind: The New Science of the Meme (1995). The concept of mental viruses was explored deeply and popularized by Richard Dawkins, who (AFAIK) coined the term "memetics". And the idea is older than that. We know, for example, that the beat author William S. Burroughs said "Language is a virus from outer space" some time in the mid '80s.