Herpes Simplex Virus (HSV) Overview

HSV-1 (oral herpes) and HSV-2 (genital herpes) are infections of the skin, mucous membranes, and can sometimes affect the central nervous system.

HSV-1 is a very common infection worldwide, with a high percentage of adults having antibodies.

HSV-2 infection is less common than HSV-1, with a lower percentage of adults having antibodies. Risk factors include multiple sexual partners and prostitution.

HSV spreads via contact with oral secretions (e.g., kissing, shared utensils), genital secretions (sexual contact, oral sex), or mucocutaneous lesions; also, mother-to-child during pregnancy.

HSV replicates initially at entry points, then travels to nerve cell bodies in ganglia, and spreads throughout the body via the nervous system.

HSV stays inactive in the sensory ganglia. Reactivation can occur due to immune system weakness.

HSV can invade the central nervous system (CNS) causing potentially life-threatening encephalitis, mainly through the nerve pathways.

The body initially fights HSV with IgM antibodies, followed by IgG; cellular immunity plays a vital role, especially in preventing reactivation of the infection.

HSV-1 is typically associated with oral herpes (cold sores), while HSV-2 is primarily linked to genital herpes.

This occurs when a newborn comes into contact with infected vaginal secretions during delivery. It can also happen transplacentally or postpartum.

The virus can become active again, causing symptoms even after a period of dormancy. This happens due to weakened immune systems.

Symptoms vary depending on location and infection stage. They can include fever, skin lesions (vesicles, ulcers), pain, dysuria, and neurological issues in severe cases.

Antiviral medications are used to manage symptoms and reduce viral shedding. There is no cure for HSV infections.

Severe complications can include encephalitis, pneumonia, hepatitis, and neurological sequelae.

Usually diagnosed based on clinical presentation and sometimes confirmed by laboratory tests.

The time between exposure to the HSV virus and the onset of symptoms can range from 2 to 12 days.

Early HSV infection can be asymptomatic or involve skin and mucous membrane lesions, sometimes accompanied by fever, body aches, and general weakness.

These infections are common in children and young adults, mostly caused by HSV-1, and involve sores in the mouth and throat.

This is the most common form of recurrent herpes infection, marked by blisters around the mouth, often preceded by itching or burning.

This infection affects fingers, particularly the index finger of the dominant hand, causing vesicles, swelling, redness, and pain.

This infection is common in contact sports, caused by skin-to-skin contact with an infected person, resulting in blisters on various areas of the body.

This occurs when HSV infection affects someone with eczema, leading to widespread herpes lesions.

HSV can infect the cornea, resulting in potential blindness, characterized by pain, light sensitivity, and red eye.

Tzanck smears from vesicular (blister) lesions show giant cells with intranuclear inclusions, a characteristic of HSV infection.

Serum IgM antibodies against HSV-1 or 2 indicate a primary infection or reactivation. IgG antibodies indicate chronic infection, not necessarily current disease.

HSV can be grown in cell cultures, where it causes characteristic changes (cytopathic effect), confirming the presence of the virus.

Viral DNA can be detected in the fluid from blisters using a polymerase chain reaction (PCR) test, which amplifies viral DNA.

Examining the cerebrospinal fluid (CSF) reveals increased white blood cells (lymphocytes) - a sign of inflammation, sometimes with red blood cells indicating bleeding in the brain.

In HSV encephalitis, protein levels in the CSF are moderately increased, while glucose levels remain normal, distinguishing it from other infections.

Acyclovir is an antiviral medicine that inhibits viral DNA polymerase, preventing the virus from replicating. It is used orally or intravenously depending on the severity of the infection.

Long-term treatment with Valaciclovir or Famciclovir is used to prevent recurrent outbreaks in people with frequent infections or those with weakened immune systems.