Does a hotel legally have to tell you if something in the room could be harmful?

I stayed at a small hotel while on my travels and during my stay was severely bitten by "bed bugs". The manager of the hotel had knowledge of an infestation in not just my room, but several rooms on my floor. He however neglected to mention anything as if everything was perfectly fine. The morning after the bug bites happened, I went to the front desk to demand to speak with the manager. I requested a room change, and if not that, a refund. I was denied both, saying that it was not there problem and that they would do nothing. Is there a law stating that a they must take responsibility or at least inform guest of possible harm?