Well, it is very rare for a wolf to attack a human being. But yes, it has happened in the past. If the wolves are in a famine, they may attack a human. Or if the wolf just happen to be rabid.
Otherwise, people shouldn't be terrified of the wolves. Well... just don't be stupid enough to scream and then run. Just... walk away. Otherwise, they'll just feel provoked. I know it did happen in Canada before, but I don't recall hearing about any cases in the USA.
Last January, I heard that a man in Saskatchewan got attacked by a timber wolf. Though the man did survive, but he had to get a lot of stitches. He was bitten on the back, arm, leg and groin. (ouch)
CBC News - Wolf attacks Saskatchewan man
Like I said, it's pretty rare for a wolf to attack a human unless the wolf is starved to death, or just plainly rabid. Also, you won't get turned into a werewolf if you get bitten by one. 
Wolves are part of the canine family, they are just bound to attack people like many other dog breeds. But they often live in isolation rather than where people live.
