Westover Heights Clinic - Herpes Viruses

    Viruses cause herpes infections. A virus is a microscopic organism that invades cells and, while it is there, disrupts the normal activities of the cell.  There are eight human herpes viruses. They include herpes simplex 1 (HSV 1), herpes simplex 2 (HSV 2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpes virus 6 (HHV 6), human herpes virus 7 (HHV 7), and human herpes virus 8 (HHV 8).

    HSV 1 is the virus usually associated with cold sores (also called fever blisters) that occur on the lips, nose, chin, and other parts of the face.  Many HSV 1 infections are contracted during childhood, and most infections go completely unnoticed because the symptoms can be minor or not apparent. About 56% of people over age 14 in the United States display evidence of a previous HSV 1 infection when their blood is tested for HSV 1 antibodies.  The percentage is declining over time, perhaps as more people recognize that "herpes" causes cold sores and more care is taken not to kiss others when cold sores are present.

    HSV 2 is the virus usually associated with genital herpes infections. About 22% of people in the US over the age of 12 show evidence of HSV 2 infection when their blood is tested by a test that accurately distinguishes between HSV 1 and 2. Of those infected with HSV 2, only about 10% know it.

    Varicella-zoster is the virus responsible for chicken pox and for shingles (also called herpes zoster).  After a person recovers from the outbreak of chicken pox sores, the virus remains in the body in the nerve cells. At some point in the future, the virus can again travel to the surface of the skin and cause the disease called shingles. Shingles is characterized by painful blistery sores on one side of the body only.  It can appear anywhere, but most often, it appears on the chest, back, or face.  In older people especially, shingles can be an unpleasant ordeal. Even after the blisters are gone the pain can remain for months. This is called post herpetic neuralgia.  Although shingles blisters can look a little like HSV 1 or 2, it is not the same thing, and an experienced professional can determine the difference with accurate testing.  But sometimes the two (simplex and zoster) get mixed up. The way to tell the difference is that simplex recurs but zoster almost never does.  Only 3% to 4% of people who get zoster ever have a recurrence, and of those who do, almost no one recurs again unless they have a highly compromised immune system.  There is now a vaccine called Zostavax that reduces by half the risk of getting shingles.  This vaccine is approved for people age 60 and over.  The cost is about $175 and is strongly recommended to reduce the risk of getting shingles and post herpetic neuralgia.

    Epstein-Barr virus is the most common cause of mononucleosis.  Most adults will test positive for Epstein-Barr antibody, even if they have never had recognized mononucleosis.

    Cytomegalovirus (CMV) infections in healthy adults usually go unnoticed.  Most adults show evidence in blood tests of having been infected with cytomegalovirus.  However, if a mother first contracts CMV while she is pregnant, it can cause serious problems in the unborn baby.  Cytomegalovirus is also a problem for people whose immune systems are not functioning properly like those who have HIV or AIDS.

    Human herpes virus type 6 causes roseola in children. Human herpes virus type 7 causes a rash in slightly older children.  Human herpes virus type 8 causes Kaposis sarcoma (KS), an infection seen mostly in AIDS patients but occasionally in other populations, too.

    If you have further questions about varicella zoster, Epstein Barr, CMV, or HHV 6, 7, or 8, you may wish to contact your clinician. The rest of this book discusses only the herpes simplex viruses.  When the word "herpes" is used, it will refer to genital herpes infections unless otherwise stated.