i don't think jenova was literally a "virus," but the disease it infected others with spread much like one. A true "virus" is not any type of living cell-it's just some DNA wrapped in a protein coating. The only way for a virus to reproduce it for it to invade a living cell, in which the cell itself takes the virus's DNA and uses it to create new viruses. so to say that jenova itself, being a living, multi-celled creature, was a "virus" is false, although it would transfer its own cells to others to make them diseased. Ifalna made the innocent mistake of using the word "virus" when she really meant "disease".