Overview
Varicella zoster virus is a DNA virus belonging to the herpesvirus group. It causes varicella or chickenpox as the primary infection and herpes zoster or shingles due to reactivation of the latent virus. After primary infection, the virus remains dormant in sensory nerve ganglia and can reactivate later in life. Varicella zoster PCR qualitative test is the optimal method for detecting active infection. It detects varicella zoster virus genetic material in clinical samples. The test is highly sensitive and specific, and is especially useful in early infection and atypical presentations
Symptoms
Chickenpox commonly 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 presents as a painful, unilateral vesicular rash along the distribution of a sensory nerve. Burning sensation, tingling, fever, and headache may precede the rash. Symptoms are usually more severe in adults.
Complications include pneumonia, encephalitis, bacterial skin infections, and postherpetic neuralgia. Disease severity is higher in adults, pregnant women, and immunocompromised individuals.
Causes
Varicella zoster virus enters the body through the respiratory tract or conjunctiva. It replicates in the nasopharynx and regional lymph nodes, followed by viremia that spreads the virus to the skin and other organs.
Primary infection results in chickenpox. After recovery, the virus remains latent in sensory ganglia. Reactivation of the virus later in life causes herpes zoster.
PCR positivity is highest when samples are collected early, ideally within 3 to 5 days after the onset of symptoms. Vesicular fluid and cerebrospinal fluid are the preferred specimens.
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 the risk of transmission.
Infants, adolescents, adults, pregnant women, and individuals with weakened immune systems 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 herpes zoster due to a decline in cell-mediated immunity. Stress and chronic illnesses may also trigger viral reactivation.
Prevention
Vaccination is the most effective method for preventing varicella infection. Immunization significantly reduces disease severity and complications.
Early diagnosis using PCR allows timely isolation and appropriate management, reducing transmission. Proper sample collection, transport, and storage are essential to avoid false negative results.
Avoiding contact with active lesions, maintaining good hygiene, and monitoring high-risk individuals help prevent spread and complications. In immunocompromised patients, early detection and antiviral therapy reduce disease severity.
