Herpes Simplex Virus: An Important Etiology for Secondary Glaucoma Relief Jones III, MD Louis R. Pasquale, MD Deborah Pavan-Langston, MD ’ HSV: A Basic Introduction The herpes simplex virus (HSV) is an extremely successful parasite in humans. It typically remains associated with a host throughout life, can achieve sophisticated stages of parasitism, and is one of the most common causes of infection in man. There are 2 distinct serotypes of HSV: HSV type 1 (HSV-1) and type 2 (HSV-2). They are transmitted by direct skin or mucous membrane contact, by venereal routes, or by maternal genital infection to the newborn. HSV-1 classically causes infections above the waist, for example, the eye, nares, or mouth (cold sores); HSV-2 usually causes infections below the waist, for example, the genitals (although in some cases the reverse is true). The HSV is composed of 4 major components. The core contains double-stranded, linear DNA coiled around proteins arranged in the shape of a barbell. The core is surrounded by an icosahedral capsid that contains 162 capsomeres and measures 100 nm. Lying outside the capsid is the fibrillous tegument. These 3 structures are encased in an envelope composed of nuclear and other cell membranes. The membranes are composed of lipids and proteins. The lipids make the virus susceptible to lipid and ether solvents. Infection causes antigenic changes in the membranes of the cells they infect. Immunologic mechanisms that seek to destroy the virus also act against host cells. The wide variety of proteins in the envelope plays a role in immune responses, serodiagno- sis, and disease severity. 1 99