HSV1

Herpes simplex virus type 1 (HSV-1) is a human alphaherpesvirus in the genus Simplexvirus. It is one of the most common human viruses and typically causes orolabial herpes, such as cold sores or fever blisters around the mouth, though it can also cause genital herpes through oral-genital contact and, less commonly, ocular or other infections.

Transmission occurs mainly through close personal contact, especially via saliva or contact with active lesions. Primary infection is frequently asymptomatic but can present as gingivostomatitis in children or mild pharyngitis and fever in adults. After the primary infection, HSV-1 travels to sensory nerve ganglia and establishes lifelong latency, most often in the trigeminal ganglion. Reactivation triggers recurrent lesions at or near the original site and, in some cases, other mucosal surfaces or tissues.

Epidemiologically, HSV-1 is highly prevalent worldwide, with seroprevalence increasing with age. Many infections are acquired during childhood, and asymptomatic viral shedding can occur even without visible symptoms.

Diagnosis is usually clinical, supported by laboratory testing such as PCR from lesion swabs, viral culture, or serology for antibodies when appropriate. There is no cure for HSV-1, but antiviral medications—acyclovir, valacyclovir, and famciclovir—can reduce the duration and severity of outbreaks and may be used episodically or as suppressive therapy to reduce recurrences or asymptomatic shedding.

Prevention focuses on avoiding contact during outbreaks, practicing good hygiene, and using barriers when appropriate; a globally effective HSV-1 vaccine is not yet available. Complications can include keratitis and, rarely, encephalitis, particularly in neonates and immunocompromised individuals.