Effects of the Herpes Virus

The herpes virus is actually a family of viruses, herpesviridae, the first eight of which cause disease in humans (the others cause disease in other animals). In addition to the familiar oral and genital herpes viruses, herpes viruses cause chickenpox and shingles, mononucleosis, retinitis, roseola, Kaposi's sarcoma and several other medical conditions. Human herpesviruses are numbered in the following way: HHV-1 through HHV-8 and are also referred to by more familiar names when applicable.

HHV-1

• HHV-1, also known as HSV-1, is the virus responsible for most cases of oral herpes, or cold sores. Oral herpes is also sometimes, though more rarely, caused by HHV-2. HHV-1 is transmitted through close contact with active cold sores or, according to the Mayo Clinic, through sharing things like dishes and towels.

  People with oral herpes experience prodrome, symptoms that develop before the appearance of an outbreak. Sometimes described as an "aura," this is a burning, tingling or itching sensation in the area of the skin that will be affected by the cold sore. Cold sores are blisters filled with fluid. They eventually break and form a crust. The Mayo Clinic reports that an outbreak of oral herpes generally lasts for a week or slightly more.

HHV-2

• Genital herpes is caused by HHV-2 (HSV-2), although it is also sometimes triggered by infection with HHV-1. Like HHV-1, HHV-2 can be contracted through close contact with blisters or through the use of shared towels and other articles; however, it can also be contracted through contact with skin that is not currently affected by an outbreak; this property of HHV-2 is called asymptomatic viral shedding.

  Genital herpes is also accompanied by prodrome and a rash that blisters. According to the Centers for Disease Control and Prevention (CDC), the first rash generally occurs two weeks after the virus is contracted; outbreaks generally last between two and four weeks. Many people with HHV-2 experience no or only very mild symptoms; the same is true for HHV-1. Outbreaks may also decrease in frequency and severity over time.

HHV-3

• Varicella zoster virus (VZV) or HHV-3 is the virus that causes both chickenpox and herpes zoster (shingles). The initial infection leads to chickenpox, while a recurrence, which may happen years or decades later, leads to shingles.

  Shingles causes a rash and blisters much like chickenpox, but it is limited to the nerve in which VZV had been latent. Shingles also causes pain along this nerve; the pain can vary in intensity from mild to very severe. Sometimes this pain does not clear up at the same time as the shingles rash. This condition is known as postherpetic neuralgia, and it can last for months or years. A recurrence of shingles is also possible.

HHV-4

• HHV-4 is also known as Epstein-Barr virus (EBV). This virus leads to infectious mononucleosis when it infects young adults, according to the CDC. It also contributes to the incidence of malignancies like some lymphomas and nasopharyngeal carcinoma among others, according to J.L. Hsu and S.L. Glaser of the Northern California Cancer Center. It also leads to hairy leukoplakia, an oral condition, in people with HIV.

HHV-5--HHV-8

• HHV-5, also known as cytomegalovirus (CMV), is a common infection that does not cause disease in healthy people but which may cause developmental problems if passed from mother to child. It is also a serious health concern for people with weakened immune systems, such as people with HIV, in whom it may lead to retinitis, a condition which can cause blindness.

  Both HHV-6 and HHV-7 cause roseola, a childhood illness. According to the Mayo Clinic, roseola leads to fever, rash, irritability and fatigue, diarrhea and loss of appetite as well as swollen eyelids.

  HHV-8 has been linked to Kaposi's sarcoma, a skin cancer that causes purple lesions and is found in people with AIDS and in some other populations.