The problem I see with this is simple:
If you take away the virus ability to work on some of the powerful bots like that one, nobody will use it.
Though I'm not so sure about DoomBots in particular; never actually virused one, I just shoot them. Their ability sounds unpleasant but I've not really seen it activate much. Why not just put a cap on it? Having it go too far is kinda pointless anyway. On higher difficulties the player cant have all that much health to begin with, and on lower ones you dont want it doing like 3000 damage and killing those players instantly, because it's supposed to be easy mode.