Virus

Herpesviruses are enveloped, double-stranded DNA viruses. Of the more than 50 herpes viruses that exist, only eight cause disease in humans. These include the human herpes virus types 1 and 2 that cause cold sores and genital herpes; human herpes virus 3, or varicellazoster virus (VZV), that causes chicken pox and shingles; cytomegalovirus (CMV), a virus that in some individuals attacks the cells of the eye and leads to blindness; human herpes virus 4, or Epstein-Barr virus (EBV), which has been implicated in a cancer called Burkitt's lymphoma; and human herpes virus types 6 and 7, newly discovered viruses that infect white blood cells. In addition, herpes B virus is a virus that infects monkeys and can be transmitted to humans by handling infected monkeys.