A warning was issued Wednesday about a flesh eating sexually transmitted disease that is making a comeback.It sounds like something out of a horror movie, but researchers warn it's real.A British woman contracted the rare STD that devours the flesh around the genitals. It is spread through sexual intercourse with an infected person.The disease is painless, according to the Centers for Disease Control and Prevention. It is usually found in tropical countries, but was recently discovered for the first time in England.