Contributor: Gordon K. Klintworth
Herpes simplex is a group of acute viral infections caused by several distinct serotypes of Herpes simplex virus type 1 and Herpes simplex virus type 2. The infection is  extremely common and is characterized by the development of one or more fluid filled vesicles with an elevated erythematous base in the epithelium of  the skin or a mucous membrane. Following a primary infection recurrences occur following reactivation of latent virus. Herpes simplex type 1 generally affects areas above the waist and Herpes simplex type 2 involves mainly the body surfaces below the waist. Human herpesvirus 1 may induces primary disease in the eyelid, conjunctiva or cornea. The corneal epithelium develops dendritic ulcers in recurrent disease. Herpes simplex can become latent in the posterior root ganglion or in a cranial sensory ganglion, such as the trigeminal ganglion. The viruses remain latent in different cells and tissues and they all can produce life-long infections. Herpes simplex virus type 1 and Herpes simplex virus type 2 can cause the acute retinal necrosis syndrome