Herpes simplex virus

Herpes simplex virus (HSV), also known as human herpesvirus (HHV) and herpes virus, is a double-stranded DNA virus belonging to the Herpesviridae family<ref>Whitley, RJ,

 Herpesviruses, 
 Medical Microbiology, 
 
 Vol. 4,
 
 
 
 
 
 Full text,</ref>. HSV is responsible for causing herpes infections in humans. There are two types of herpes simplex viruses: HSV-1 and HSV-2<ref>Looker, KJ, 
 Global Estimates of Prevalent and Incident Herpes Simplex Virus Type 2 Infections in 2012, 
 PLoSONE, 
 
 Vol. 10(Issue: 1),
 pp. e114989,
 DOI: 10.1371/journal.pone.0114989,</ref>.

Herpes simplex virus

3D reconstruction of the HSV-1 capsid

Herpes Simplex Virus 2

Micrograph showing the viral cytopathic effect of HSV (multinucleation, ground glass chromatin)

Herpes Simplex Virus Type 1 (HSV-1)

HSV-1 primarily causes cold sores or fever blisters on the lips, nostrils, and around the mouth<ref>Kriesel, JD,

 Herpes simplex virus infections, 
 Acta Dermato-Venereologica, 
 
 Vol. 101(Issue: 1),
 pp. adv00374,
 DOI: 10.2340/00015555-3601,</ref>. Although it can also lead to genital herpes, HSV-1 infection in the genital area is less common than HSV-2. Transmission of HSV-1 often occurs through non-sexual routes, such as direct skin-to-skin contact, sharing utensils or drinks, and kissing<ref>James, WD, 
 Herpes Simplex, 
 Andrews' Diseases of the Skin: Clinical Dermatology, 
 
 Vol. 10,
 pp. 435–445,</ref>.

Herpes Simplex Virus Type 2 (HSV-2)

HSV-2 is the primary cause of genital herpes, resulting in sores on the external and internal sex organs and glands<ref>Cohen, J,

 Genital Herpes Simplex Virus Type 2 Shedding is Increased in HIV-Infected Women, 
 Annals of Internal Medicine, 
 
 Vol. 140(Issue: 11),
 pp. 905–912,
 DOI: 10.7326/0003-4819-140-11-200406010-00011,</ref>. HSV-2 transmission occurs mainly through sexual contact, including vaginal, anal, and oral sex<ref>Tronstein, E, 
 Genital Shedding of Herpes Simplex Virus Among Symptomatic and Asymptomatic Persons with HSV-2 Infection, 
 JAMA, 
 
 Vol. 305(Issue: 14),
 pp. 1441–1449,
 DOI: 10.1001/jama.2011.420,</ref>.

Symptoms and Clinical Presentation

Symptoms of herpes infections can vary greatly between individuals. Some people may have no symptoms or very mild symptoms, while others may experience more severe or recurrent outbreaks<ref>Wald, A,

 Symptom Severity and Quality of Life in Persons with HSV: A Herpevac Trial for Women, 
 Sexually Transmitted Diseases, 
 
 Vol. 33(Issue: 8),
 pp. 508–514,
 DOI: 10.1097/01.olq.0000204667.37065.32,</ref>. Common symptoms of herpes infections include:

• Painful blisters or ulcers on the skin or mucous membranes
• Itching, burning, or tingling sensations near the affected area
• Flu-like symptoms, such as fever, headache, and muscle aches
• Swollen lymph nodes in the groin area (especially for HSV-2)
• The initial herpes outbreak is typically the most severe, with symptoms often subsiding over time. However, both HSV-1 and HSV-2 can remain dormant in the body and reactivate, leading to recurrent outbreaks<ref>Roizman, B,

 The Life and Times of Herpes Simplex Virus, 
 American Scientist, 
 
 Vol. 95(Issue: 4),
 pp. 320–327,
 DOI: 10.1511/2007.66.364,</ref>.

Diagnosis and Treatment

Diagnosis of herpes infections is typically based on the appearance of lesions, patient history, and laboratory tests such as viral culture, polymerase chain reaction (PCR), and serologic testing for HSV antibodies<ref>Cherpes, TL,

 Herpes Simplex Virus Reactivation and Diagnosis of Genital Herpes, 
 Clinical Microbiology Newsletter, 
 
 Vol. 25(Issue: 18),
 pp. 137–142,
 DOI: 10.1016/S0196-4399(03)80037-6,</ref>.

While there is currently no cure for herpes infections, antiviral medications such as acyclovir, famciclovir, and valacyclovir can help manage symptoms, reduce the severity and duration of outbreaks, and lower the risk of transmission to sexual partners<ref>Koelle, DM,

 Antiviral Therapy for Herpes Simplex Virus Infections: An Update, 
 Expert Opinion on Pharmacotherapy, 
 
 Vol. 9(Issue: 4),
 pp. 579–592,
 DOI: 10.1517/14656566.9.4.579,</ref>. Additionally, practicing safe sex and good hygiene can help reduce the risk of contracting or transmitting HSV<ref>Corey, L, 
 The Current and Future Role of Drugs in the Management of Genital Herpes, 
 Expert Opinion on Pharmacotherapy, 
 
 Vol. 10(Issue: 11),
 pp. 1759–1770,
 DOI: 10.1517/14656560903037126,</ref>.

Prevention

To prevent the spread of herpes infections, individuals should:

• Abstain from oral, vaginal, or anal sex when experiencing active herpes outbreaks or prodromal symptoms
• Use barrier protection, such as condoms and dental dams, during sexual activity
• Avoid sharing personal items like towels, razors, or utensils with someone who has an active outbreak
• Wash hands frequently and avoid touching the affected area to minimize the risk of autoinoculation and transmission to others<ref>Pinninti, SG,

 Maternal and Neonatal Herpes Simplex Virus Infections, 
 American Journal of Perinatology, 
 
 Vol. 31(Issue: 12),
 pp. 1133–1140,
 DOI: 10.1055/s-0034-1372427,</ref>.

Individuals with genital herpes should also inform their sexual partners about their infection and discuss the risks involved in sexual activity. Regular testing for sexually transmitted infections (STIs) can help identify asymptomatic cases and reduce the spread of HSV and other STIs<ref>Workowski, KA,

 Sexually Transmitted Diseases Treatment Guidelines, 2015, 
 MMWR Recommendations and Reports, 
 
 Vol. 64(Issue: 3),
 pp. 1–137,
 
 
 
 
 Full text,</ref>.

While there is currently no approved vaccine for herpes simplex virus, ongoing research aims to develop effective vaccines that could prevent or reduce the severity of HSV infections<ref>Stanberry, LR,

 Prospects for Control of Herpes Simplex Virus Disease through Immunization, 
 Clinical Infectious Diseases, 
 
 Vol. 38(Issue: 5),
 pp. 633–639,
 DOI: 10.1086/381571,</ref>. In the meantime, practicing good hygiene, safe sex, and open communication can significantly reduce the risk of transmission and help manage herpes infections.

Summary

Herpes simplex virus (HER-peez SIM-plex VY-rus) is a type of virus that causes herpes infections and has DNA as its genetic material. There are two types of herpes simplex viruses. Infections with type 1 viruses cause cold sores on the lips or nostrils. Infections with type 2 viruses cause sores on the genitals (external and internal sex organs and glands). Also called HHV, HSV, and human herpesvirus.