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]
These herpes viruses enter the body through small cuts, abrasions, or breaks in the skin or mucous membranes. The incubation period for herpes simplex infections is about three to six days. Transmission (spread) of the virus is person to person and more likely to occur if blisters or lesions are present. The majority enter after an uninfected person has direct contact with someone carrying the virus (either with or without noticeable lesions). Simply touching an infected person is often the way children get exposed. Adolescents and adults frequently get exposed by skin contact but may get their first exposure by kissing or sexual contact (oral and/or genital contact), especially for HSV-2. Statistical studies suggest that about 80%-90% of people in the U.S. have been exposed to HSV-1 and about 30% have been exposed to HSV-2. Usually, the contagious period continues until lesions heal. Some people (estimated from 30%-50%) occasionally shed herpes virus while having few or no associated symptoms or signs.
The herpes simplex virus is probably the most well-known virus of the herpes family, and it is just as contagious. Herpes simplex infects epithelial cells and remains latent in neurons. HSV-1 causes recurrent oropharyngeal lesions, commonly known as “fever blisters" or "cold sores.” It is also the primary cause of sporadic encephalitis (inflammation of the brain), gingivostomatitis (inflammation of the gums and mucous lining of the mouth), and keratoconjunctivitis (severe dryness of the eye that involves the cornea) and dendritic corneal ulcers (also called HSV keratitis) in which the cornea becomes affected by herpetic lesions that look like the dendrites of neurons in the brain.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
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]

If you are pregnant and have genital herpes, it is very important for you to go to prenatal care visits. Tell your doctor if you have ever had symptoms of, or have been diagnosed with, genital herpes. Also tell your doctor if you have ever been exposed to genital herpes. There is some research that suggests that genital herpes infection may lead to miscarriage, or could make it more likely for you to deliver your baby too early.
A scary finding is that more cases of genital herpes than ever before are now being caused by HSV-1 (the type most people assume only causes mouth sores), and about 85 percent of people with genital herpes don’t even know it. (7) Studies show that about 50 percent of the new genital herpes infections in young adults are due to HSV-1 and about 40 percent in older adults. The fact that most people don’t ever find out they’re infected is one of the reasons that transmission rates are steadily climbing.
Recurrent outbreaks of genital herpes may happen, with some patients having four to six outbreaks in the span of a year. Compared to the first infection, subsequent recurrences are less painful and occur in shorter periods than the first infection. There are some patients, however, who don’t have another outbreak for many years or even once more during their lifetime.11

Oral herpes (HSV-1) infection (or exposure without noticeable infection) is common. About 65% of the U.S. population has detectable antibodies to HSV-1 by age 40. This article will focus on HSV-1, or oral herpes, not on HSV-2, also commonly known as genital herpes. Genital herpes is considered to be a sexually transmitted disease (STD). In addition, HSV-2 virus should not be confused with human papillomavirus (HPV), the cause of genital warts, and some cervical and other cancer types.
Prodrome: Early in the phase of reactivation (also called an outbreak), many people experience an itching, tingling, or painful feeling in the area where their recurrent lesions will develop. This sort of warning symptom – called a “prodrome” – often comes a day or two before lesions appear. To be on the safe side, it’s best to assume virus is active (and, therefore, can be spread through direct skin-to-skin contact) during these times.
Both HSV-1 and HSV-2 infections are acquired from direct contact with someone who carries the virus. The infectious secretions that pass on HSV-1 or HSV-2 live on oral, genital or anal mucosal surfaces. They’re passed through skin-to-skin transmission, and any form of direct contact with sores on the mouth, buttocks or genitals can cause the virus to be passed.
In order to diagnose herpes, a health care provider can swab an area of visibly active herpes infection or, if symptoms aren’t active, a blood test can be given that measures the number of herpes antibodies present in the body. The antibodies don’t indicate herpes itself, but rather show the immune system’s response to the presence of the virus in the body. It’s important to note that sometimes a swab can give false negative results since herpes lesions need to be large enough to yield enough detectable virus and if the outbreak is already healing it also may not be detected in a swab. (6)
Worldwide rates of either HSV-1 and/or HSV-2 are between 60 and 95% in adults.[4] HSV-1 is more common than HSV-2, with rates of both increasing as people age.[4] HSV-1 rates 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 or 16% of the population worldwide were infected with HSV-2 as of 2003 with greater rates among women and in those in the developing world.[10] Rates of infection are determined by the presence of antibodies against either viral species.[81]
Herpes antiviral therapy began in the early 1960s with the experimental use of medications that interfered with viral replication called deoxyribonucleic acid (DNA) inhibitors. The original use was against normally fatal or debilitating illnesses such as adult encephalitis,[92] keratitis,[93] in immunocompromised (transplant) patients,[94] or disseminated herpes zoster.[95] The original compounds used were 5-iodo-2'-deoxyuridine, AKA idoxuridine, IUdR, or(IDU) and 1-β-D-arabinofuranosylcytosine or ara-C,[96] later marketed under the name cytosar or cytarabine. The usage expanded to include topical treatment of herpes simplex,[97] zoster, and varicella.[98] Some trials combined different antivirals with differing results.[92] The introduction of 9-β-D-arabinofuranosyladenine, (ara-A or vidarabine), considerably less toxic than ara-C, in the mid-1970s, heralded the way for the beginning of regular neonatal antiviral treatment. Vidarabine was the first systemically administered antiviral medication with activity against HSV for which therapeutic efficacy outweighed toxicity for the management of life-threatening HSV disease. Intravenous vidarabine was licensed for use by the U.S. Food and Drug Administration in 1977. Other experimental antivirals of that period included: heparin,[99] trifluorothymidine (TFT),[100] Ribivarin,[101] interferon,[102] Virazole,[103] and 5-methoxymethyl-2'-deoxyuridine (MMUdR).[104] The introduction of 9-(2-hydroxyethoxymethyl)guanine, AKA aciclovir, in the late 1970s[105] raised antiviral treatment another notch and led to vidarabine vs. aciclovir trials in the late 1980s.[106] The lower toxicity and ease of administration over vidarabine has led to aciclovir becoming the drug of choice for herpes treatment after it was licensed by the FDA in 1998.[107] Another advantage in the treatment of neonatal herpes included greater reductions in mortality and morbidity with increased dosages, which did not occur when compared with increased dosages of vidarabine.[107] However, aciclovir seems to inhibit antibody response, and newborns on aciclovir antiviral treatment experienced a slower rise in antibody titer than those on vidarabine.[107]
Avoid touching any sores you have. If you do, wash your hands with soap and water. You should avoid sex while you have sores, and use a male or female condom or dental dam with your partner if sex occurs despite intentions to not have sex. Herpes is most contagious during an outbreak, but it’s also possible to spread herpes when no symptoms are present.
Oral herpes, commonly referred to as mouth herpes, is a viral infection of the mouth and gums primarily by the Herpes simplex virus type 1 (HSV-1) but may also be due to the genital variant (HSV-2). It is also known as recurrent herpetic stomatitis or acute herpetic gingivostomatitis. The infection of the mouth typically causes small fluid-filled blisters known as vesicles on the roof of the mouth (palate), inside of the cheeks (buccal muscosa), tongue, gums and even the lips (herpes labialis). It may also occur on the skin around the mouth and extend to the nose and into the nasal cavity.
Although the cause is unknown, outbreaks are often associated with periods of weakened immune systems, skin wounds, menstruation, fever, nerve damage, tissue damage from surgery, or exposure to extreme climate situations. A genital herpes outbreak or episode occurs when the HSV-1 or HSV-2 virus is reactivated from its dormant stage. Genital herpes is an incurable disease, and once you contract it, you may experience outbreaks throughout your lifetime. Those who are experiencing their first herpes episode of genital herpes can expect to have several (typically four or five) outbreaks within a year. Over time these recurrences usually decrease in frequency and severity. The first outbreak of herpes is often the longest outbreak experienced. After that, short and inconsistent episodes can be managed and treated with antiviral medication.

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]
Herpes infection can cause sores or breaks in the skin or lining of the mouth, vagina, and rectum. This provides a way for HIV to enter the body. Even without visible sores, having genital herpes increases the number of CD4 cells (the cells that HIV targets for entry into the body) found in the lining of the genitals. When a person has both HIV and genital herpes, the chances are higher that HIV will be spread to an HIV-uninfected sex partner during sexual contact with their partner’s mouth, vagina, or rectum.
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