One of the most common versions is that one who becomes a rougarou will remain under that spell for 101 days. When the 101 days are up the curse is transferred to another person by blood sucking. The original rougarou then returns to a normal human -- yet, if he tells anyone about his experience, he will be killed by the one he drew blood from. That seems rather ungrateful, but one cannot tell a rougarou what not to do.
As summer comes close to ending and cooler weather approaches, tales of the rougarou begin anew and are often embellished year after year. And the closer it gets to Halloween, the more outlandish the stories get. It has been known that the creature will roam the streets at night, antagonizing everyone it meets until someone stabs or shoots it. The rougarou will purposely do this because at the first drop of blood, it returns to the original human form. He can then tell his attacker who he really is. The trick is, though, that the person who attacked the rougarou cannot tell you, or anyone, about this for 101 days -- or he, too, will become a rougarou.
Now then, there are ways to keep the rougarou away from you. You can roll up a leaf from the swamps and keep it in your wallet. Or, if you are creative, paint a hexagon shape on the middle of your floor, stand in the center of it, and say prayers to protect you. However, if you do not believe the rougarou stories are true, and you do nothing, you may be heading for a bout or two with a rougarou.
So, it stands to reason that if you do intend to visit around the Bayou areas, you should not be doing any rougarouing (staying out late and running around the streets) -- unless you think you might be staying for at least 101 days.
http://www.bellaonline.com/articles/art45044.asp