herpes

Any of several infectious diseases caused by viruses of the herpes group. Herpes simplex I is the causative agent of a common inflammation, the cold sore. Herpes simplex II is responsible for genital herpes, a highly contagious, sexually transmitted disease characterized by painful blisters in the genital area. It can be transmitted in the birth canal from mother to newborn. Herpes zoster causes shingles; another herpes virus causes chickenpox.

A number of antivirals treat these infections, which are particularly troublesome in patients whose immune systems have been suppressed medically; for example, after a transplant operation. The drug acyclovir, originally introduced for the treatment of genital herpes, has now been shown to modify the course of chickenpox and the related condition shingles, by reducing the duration of the illness.

A vaccine for shingles was tested by US researchers in 1999.