The Real Apocalypse: Rage Virus

We've all seen 28 Days/Weeks Later. The movies revolve around a "rage virus" that spreads throughout the population creating chaos and zombie like effects in humans. We all know that these movies are just fictional stories and couldn't happen in real life...or could they?

Recently while combing The New Scientist, an awesome website I've just discovered, I came across this gem: Mass hysteria breaks out in central America

The article links on to other historical accounts of this mysterious "rage virus". There are some disturbing information in some of the linked articles. For instance:

• Pro Med Mail -The strange illness apparently affects young people more than old, putting them in a trance and giving them super-human strength, according to Knight and other witnesses. "A 15-year-old girl with siknis can overpower 6 or 7 men," Knight said. "The men can't detain her, and have to tie her up in bed sheets.".....Sometimes, however, grisi siknis can turn violent. In the case of Raiti in 2003, some of the affected people ran around town with machetes trying to cut others....
• Pub Med - Several explanations had been put forward initially by the community : bioterrorism, noxious fumes and "bad spirits."

It seems, though, that it's mostly explained away by stress in large groups. That makes sense to a certain degree, however, what's intriguing to me is the virus like qualities and the symptoms of all of the "infected".

Could this become a larger epidemic?