Do I have legal recourse against someone relentlessly, falsely and publicly claiming I have genital ?

The gentleman in question simply frequents a web forum I chat in. I have never met this person, nor do I personally know anyone he knows. He decided to use all the personal information he could gather about me to create a posting on http://stdcarriers.com/ saying I am infected with genital . It is not written in such a way as to be satire....it is definitely meant to be taken literally. I know his first and last name and how to contact him, but not much other than that. Is there an agency I can report this to that will help me find more specific contact info on this person and possibly prosecute? He has also claimed on other websites that I am a pedophile and a rapist. He uses my first and last name and has also posted my phone number along with some of these claims.