Though if yomintz will ever see this, I don't know. This is at the beginning of a book a friend suggested I read : "Snow Crash", by Neal Stephenson. (FWIW, it looks as though the book's going to have more social commentary in it than story, but we shall see; I've barely started.) Anyway, on the top of the page where Chapter 1 begins are three dictionary definitions. It's the 3rd one, third def. that is of import here :

VIRUS....[L. virus slimy liquid, poison, offensive odour or taste.] 1. Venom, such as is emitted by a poisonous animal. 2. Path: a. A morbid principle or poisonous substance produced in the body as the result of some disease, esp. one capable of being introduced into other persons or animals by inoculations or otherwise and of developing the same disease in them... 3. fig A moral or intellectual poison, or poisonous influence.
---The Oxford English Dictionary