Exactly what it says on the tin. Pandemic lycanthropy threatens western society.
The disease, transmitted through blood contact and sexual fluids, is fairly innocuous for the first couple of weeks or so. The only known symptoms are lack of pupil dilation, increased sex drive, and increased perspiration and heart rate. When an infected individual sees the full moon, they transform painfully into a hairy quadrupedal beast that lacks pretty much any drive or emotion save hunger and lust.
No one knows where the disease came from, as best scientists can tell, it's a virus that infects the brain and endocrine system and causes a powerful psychosomatic reaction upon sighting the full moon. It is extremely difficult to tell, however, when you're being torn to pieces by a nominally sentient monstrosity.
Basically, this is a game inspired by the book I am Legend, except with werewolves instead of vampires. The players will play as scientists attempting to understand how to treat and cure lycanthropy in the ruins of quarantined Los Angeles. I could also use some players to play lycanthropes that end up getting experimented on. The traits and abilities of the lycanthropes will be kept vague to drive the plot of the game, and the lycanthrope players will most likely get to do a lot of the selecting what the answers to the mysteries actually are.