Varicella zoster virus

Varicella zoster virus (VZV) is one of eight herpesviruses (HHV 3) and is known to only infect humans. It causes varicella (chickenpox) upon initial infection, and can reactivate to cause herpes zoster (shingles). After initial infection, VZV establishes a latent infection in the body.

Initial infection
Varicella, or more commonly referred to as chickenpox, usually lasts 5-7 days. Typical signs and symptoms include: People who have been vaccinated against varicella can still get the disease, but it is usually a milder form. Complications can occur, but are not common in healthy, vaccinated people who get the disease. People who are at risk for complications include infants, adolescents, adults, pregnant women, and people with weakened immune systems. Complications include:
 * A rash that turns into itchy, fluid-filled blisters (turn into scabs after a week)
 * Fever
 * Tiredness
 * Loss of appetite
 * Headache
 * Bacterial infections of the skin and soft tissues
 * Pneumonia
 * infection/inflammation of the brain
 * Bleeding problems
 * Sepsis
 * Dehydration

Age of infection
Similar to Epstein-Barr virus, the age of initial infection affects the severity of the infection. In childhood (except for in infants), varicella is usually significantly less severe than in adolescence and adulthood. As a result, adolescents and adults are at risk for complications. Reactivation (zoster/shingles) also continues this pattern; older adults are more likely to have complications, with longer lasting and more severe pain.

Reactivation: Zoster/Shingles
About 1 in 3 people in the U.S. will develop zoster/shingles in their lifetime. Anybody who has had varicella/chickenpox may develop zoster (including children). People who have weakened immune systems or use immunosuppressive drugs (e.g., steroids) are at higher risk to develop zoster. Most people only have one episode of zoster, but multiple reactivations may occur. Zoster causes a painful rash on one side of the face or body. The rash consists of blisters that are accompanied by pain, itching, or tingling. Other symptoms can include fever, headache, chills, and an upset stomach.

Transmission of VZV
VZV is a highly contagious virus that spreads through touching or breathing in the virus particles that come from the chickenpox blisters. VZV can also be spread from people with zoster/shingles via the same methods of transmission, resulting in varicella/chickenpox. For most people, getting varicella/chickenpox once provides immunity for life, meaning they will not get chickenpox twice.

The best method of prevention is the chickenpox vaccine.

https://www.cdc.gov/chickenpox/about/symptoms.html

Lyme Disease
Several herpesviruses including varicella-zoster virus may cause false positives on Lyme Disease tests.

Prevalence

 * 2001, In a Belgian study, 26.8% of patients meeting the Fukuda criteria and 30.7% of patients meeting the Holmes criteria, in a cohort of 2073 CFS patients, reported cold sores and /or shingles.

Learn more

 * Wikipedia - Varicella zoster virus