Viral HSV type 1 Infection. Viral oral infections caused by herpes simplex virus type 1 usually appear as a cluster of vesicles or punctate ulcerations on the lips or mucosa, causing extreme pain and gingival inflammation and swelling. (See Photo 8.) Fever, malaise, myalgia, and lymphadenopathy may also be present.

Cold sores are caused by the herpes simplex virus, and they're contagious.

Canker sores, which aren't contagious, are ulcers that occur in the soft tissues inside your mouth, places where cold sores don't occur.

Cold sores are common. Though you can't cure or prevent cold sores, you can take steps to reduce their frequency and to limit the duration of an occurrence.

The Herpes Simplex Virus The word "herpes" is taken from the Greek word "herpein" which means "to creep." The herpes simplex viruses are double-stranded DNA viruses that only infect humans. There are two types of herpes simplex viruses: Herpes simplex virus type 1 (HSV-1) Herpes simplex virus type 2 (HSV-2)

The herpes virus is one of the most difficult viruses to control. Scientists study how the virus works in order to understand how to combat it. It is also important for the general public to understand how this virus works because 85% of the world has been infected with one of the herpes viruses.

Herpes Simplex Virus Infections
A person can be infected with one or both herpes viruses. It has generally been believed that HSV-1 infections occurred in the mouth and HSV-2 infections occur in the genital area.