Herpes

Herpes, virus with various forms, causing painful blisters usually on the lips or genitals. The best known of several related herpes viruses is herpes simplex. It is the cause of the common cold sore (fever blister) that frequently appears on the lips. The herpes simplex infection is usually acquired before the age of 5. The virus then becomes dormant but causes recurrent blisters throughout the life of the infected person. In most instances, the sores heal within a week or two and are not serious. Herpes simplex II causes sores in, on, and around the genital organs and urinary passageways. Genital herpes can cause miscarriage, especially in the early months of pregnancy, and can also damage the central nervous system of the fetus. A third strain of the virus is called herpes zoster, or varicella-zoster virus, the cause of chicken pox and shingles. While chicken pox is commonly a childhood disease, herpes zoster generally occurs in late-middle and old age.