Human alphaherpesvirus 1

HSV-1-EM

Human alphaherpesvirus 1 (HSV-1), commonly known as herpes simplex virus 1, is a virus from the Herpesviridae family that causes Herpes simplex infections, primarily characterized by cold sores or fever blisters on or around the mouth. However, HSV-1 can also lead to genital herpes through oral-genital contact. This virus is closely related to Human alphaherpesvirus 2 (HSV-2), which is primarily associated with genital herpes.

Transmission and Infection

HSV-1 is transmitted through direct contact with infected saliva, mucous membranes, or skin lesions. The virus can enter the body through the mouth, nose, or breaks in the skin. After the initial infection, HSV-1 travels to the sensory neurons where it becomes latent and can reactivate periodically, leading to symptomatic or asymptomatic viral shedding.

Symptoms

The primary infection of HSV-1 can be asymptomatic or can cause symptoms ranging from mild to severe. The most common manifestation is gingivostomatitis, characterized by painful blisters and ulcers in and around the mouth. Recurrent infections typically present as cold sores or fever blisters on the lips. In some cases, HSV-1 can cause keratitis (inflammation of the cornea), meningitis, or encephalitis.

Diagnosis

Diagnosis of HSV-1 infection is primarily based on clinical symptoms but can be confirmed through laboratory tests such as viral culture, polymerase chain reaction (PCR) testing, and serology tests to detect the presence of HSV-specific antibodies.

Treatment

There is no cure for HSV-1 infection, but antiviral medications such as acyclovir, famciclovir, and valacyclovir can help to reduce the severity and frequency of symptoms. These medications can be used for episodic treatment or daily as suppressive therapy to reduce the risk of recurrent outbreaks and viral shedding.

Prevention

Preventive measures include avoiding direct contact with the sores of an infected individual, not sharing personal items that may have come into contact with the virus, and using barrier protection methods during oral-genital contact. For individuals with recurrent episodes, suppressive antiviral therapy may reduce the risk of transmission to others.

Epidemiology

HSV-1 is one of the most common viruses affecting humans, with a high prevalence worldwide. The rate of infection increases with age, and the majority of adults have been exposed to HSV-1 by the time they reach their forties. The transmission of HSV-1 from oral to genital areas has become more common, contributing to the rise in genital herpes cases caused by HSV-1.

See Also

• Herpes simplex virus
• Virology
• Epidemiology of herpes simplex
• Antiviral drug