According to postings flying around the web, World of Warcraft's recent expansion patch opened the world to a new plague: Corrupted Blood. The disease is contracted by fighting a new boss added to the game, and gamers have been passing it on to others in the WoW cities. Most of the NPCs have been affected and some servers are certain death for characters who cannot withstand constant repeated damage of up to 300 hit points. Amazing.
You can check out one of the original posts about the plague on ShackNews. And Evil Avatar has a link to a video that shows off the horror of Corrupted Blood in this post.