Overview
Varicella zoster virus is a DNA virus belonging to the herpesvirus group. It causes two distinct clinical conditions, varicella or chickenpox as the primary infection and herpes zoster or shingles due to reactivation of the latent virus. After initial infection, the virus remains dormant in sensory nerve ganglia and can reactivate later in life.
Varicella zoster IgG and IgM antibody testing helps determine immune status, recent infection, or past exposure. The virus is highly contagious and spreads mainly through respiratory droplets or direct contact with lesions. Infection can be severe in infants, adults, pregnant women, and immunocompromised individuals
Symptoms
Chickenpox commonly occurs in childhood and presents with fever followed by a characteristic vesicular rash. The rash usually begins on the face, chest, and back, and then spreads to the rest of the body. Associated symptoms include fatigue, headache, sore throat, and malaise.
Shingles occurs due to reactivation of the latent virus and is more common in adults and elderly individuals. It presents as a painful, unilateral rash along the distribution of a sensory nerve. Burning sensation, tingling, fever, and headache may occur before the appearance of rash.
Complications include pneumonia, encephalitis, bacterial skin infections, and postherpetic neuralgia. Disease severity is generally higher in adults than in children.
Causes
Varicella zoster infection occurs when the virus enters the body through the respiratory tract or conjunctiva. The virus replicates in the nasopharynx and regional lymph nodes, followed by viremia that spreads infection to the skin and other organs.
Primary infection results in chickenpox. After resolution, the virus becomes latent in sensory ganglia. Reactivation of the virus later in life leads to herpes zoster.
IgM antibodies appear during the acute phase of infection and indicate recent exposure. IgG antibodies develop later and indicate past infection or immunity due to vaccination.
Risk Factors
Lack of immunity due to the absence of prior infection or vaccination is the main risk factor. Close contact with infected individuals increases transmission risk.
Infants, adolescents, adults, pregnant women, and immunocompromised patients are at higher risk of severe disease. Conditions such as HIV infection, cancer, organ transplantation, and immunosuppressive therapy increase susceptibility.
Increasing age is a major risk factor for shingles due to a decline in cell-mediated immunity. Stress and chronic illnesses may also trigger reactivation.
Prevention
Vaccination is the most effective method of preventing varicella infection. Immunization provides long-term protection and reduces disease severity.
Early identification of susceptible individuals using IgG antibody testing helps guide vaccination and preventive measures. Isolation of infected individuals reduces spread, especially in hospitals and community settings.
Good hygiene practices, avoidance of contact with active lesions, and monitoring high-risk individuals help prevent complications. In immunocompromised patients, early diagnosis and antiviral therapy reduce disease severity and complications.
