Herpes is a rather common viral infection that affects a lot of people. Basically there are two types: Herpes-Zoster and Herpes-Simplex.
Herpes Zoster is caused by Varicella Zoster virus. This is the same virus that causes chicken pox. Many doctors believe that if a person ends up getting chicken pox, the virus never leaves the body of the person. The virus stays dormant and when reactivated, the virus causes herpes.
