HSV-2 is contracted through forms of sexual contact with a person who has HSV-2. An estimated 20 percent of sexually active adults in the United States are infected with HSV-2, according to the American Academy of Dermatology (AAD). HSV-2 infections are spread through contact with a herpes sore. In contrast, most people get HSV-1 from an infected person who is asymptomatic, or does not have sores.
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 type 1, which is transmitted through oral secretions or sores on the skin, can be spread through kissing or sharing objects such as toothbrushes or eating utensils. In general, a person can only get herpes type 2 infection during sexual contact with someone who has a genital HSV-2 infection. It is important to know that both HSV-1 and HSV-2 can be spread even if sores are not present.
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.
HSV-1 has been proposed as a possible cause of Alzheimer's disease.[26][27] In the presence of a certain gene variation (APOE-epsilon4 allele carriers), HSV-1 appears to be particularly damaging to the nervous system and increases one's risk of developing Alzheimer's disease. The virus interacts with the components and receptors of lipoproteins, which may lead to its development.[28][29]

A doctor will base a presumptive diagnosis on information provided by the patient and on the physical examination. The characteristic appearance of the herpes sores leaves little doubt about the diagnosis, so the typical appearance of the sores is key to the diagnosis. This appearance helps distinguish oral herpes from oral thrush, shingles, gonorrhea, and syphilis. In addition, chapped or sunburned lips can resemble oral herpes, but the tissue stain (Tzanck smear, see below) shows no virus-induced cell changes. Further testing is usually not necessary but is sometimes done.
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