Herpesviral encephalitis and herpesviral meningitis Herpes simplex encephalitis (HSE) is a rare life-threatening condition that is thought to be caused by the transmission of HSV-1 either from the nasal cavity to the brain's temporal lobe or from a peripheral site on the face, along the trigeminal nerve axon, to the brainstem.[16][17][18][19] Despite its low incidence, HSE is the most common sporadic fatal encephalitis worldwide. HSV-2 is the most common cause of Mollaret's meningitis, a type of recurrent viral meningitis.
Herpes simplex viruses -- more commonly known as herpes -- are categorized into two types: herpes type 1 (HSV-1, or oral herpes) and herpes type 2 (HSV-2, or genital herpes). Most commonly, herpes type 1 causes sores around the mouth and lips (sometimes called fever blisters or cold sores). HSV-1 can cause genital herpes, but most cases of genital herpes are caused by herpes type 2. In HSV-2, the infected person may have sores around the genitals or rectum. Although HSV-2 sores may occur in other locations, these sores usually are found below the waist.
Although it's rare, pregnant women can pass on the herpes infection to their child. This can result in a serious and sometimes deadly infection in the baby. That's why taking steps to prevent an outbreak at time of delivery is recommended starting at 34 weeks into the pregnancy. If you have signs of an active viral infection when it's time to deliver, your doctor will likely recommend a cesarean section for delivery.
Following active infection, herpes viruses establish a latent infection in sensory and autonomic ganglia of the nervous system. The double-stranded DNA of the virus is incorporated into the cell physiology by infection of the nucleus of a nerve's cell body. HSV latency is static; no virus is produced; and is controlled by a number of viral genes, including latency-associated transcript.[70]
Worldwide rates of either HSV-1 or HSV-2 are between 60% and 95% in adults.[4] HSV-1 is usually acquired during childhood.[1] Rates of both increase as people age.[4] Rates of HSV-1 are between 70% and 80% in populations of low socioeconomic status and 40% to 60% in populations of improved socioeconomic status.[4] An estimated 536 million people worldwide (16% of the population) were infected with HSV-2 as of 2003 with greater rates among women and those in the developing world.[10] Most people with HSV-2 do not realize that they are infected.[1] The name is from Greek: ἕρπης herpēs which means "to creep", referring to spreading blisters.[11] The name does not refer to latency.[12]
"When you are having an outbreak of oral herpes, symptoms usually start with a burning, itching or tingling sensation on your lips," Michael says. "This will intensify until a small rash, and then blisters, appear. These sores are commonly called 'cold sores'. The blisters are usually filled with a clear or slightly yellow liquid. Over a short time, these blisters will burst leaving a painful, raw area. These will then dry and scab over. The scabs will generally fall off after a week or two, leaving fresh clear skin beneath."
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