Infectious Diseases, Viruses

The Pretend Pox: Varicella-Zoster Virus (VZV) or Chickenpox

Author Kimberly Hazel , 05-Jul-2022

There are several different pox viruses. These viruses share several similarities, but there are also some important differences. They all cause a disease that is characterized by the development of pustules or bumps on the skin. The varicella virus, which causes chickenpox, differs from the other pox viruses. Chickenpox is caused by the varicella-zoster virus (VZV), which is a member of the herpesvirus family. In contrast, smallpox and cowpox are caused by members of the orthopoxvirus genus.


One of the most important differences between these viruses is their ability to spread from person to person. VZV is highly contagious and can easily be spread through coughing or sneezing. In contrast, orthopoxviruses are much less contagious and typically only spread through contact with pustules or scabs.


Another key difference is the severity of the diseases they cause. Chickenpox is usually a mild illness that primarily affects children. Monkeypox is more severe and is found primarily in Africa. Smallpox is much rarer than chickenpox or monkeypox, but it used to be a major global health problem. It is now eradicated thanks to vaccination programs. Cowpox is similar to smallpox but only affects cattle and does not spread to humans.




The history of the varicella-zoster virus is long and complicated. The virus that causes chickenpox is related to the viruses that cause shingles and herpes. The first recorded outbreak of chickenpox occurred in Japan in 792 AD. The disease then spread to China and other parts of Asia. From there, it is thought to have reached Europe in the Middle Ages. There are many historical accounts of chickenpox outbreaks in Europe, but the disease was not well-documented until the 18th century.

In 1767, English physician William Heberden published a paper describing the symptoms of chickenpox. He noted that the disease was particularly common in children and was generally mild. However, he also noted that some adults did develop more severe forms of the disease, which negatively impacted their health.

The disease continued to spread globally in the centuries that followed. In the late 20th century, a chickenpox vaccine became available. This has greatly reduced the incidence of the disease, but it has not eliminated it. Outbreaks still occur from time to time, usually in unvaccinated populations.


A Pox by Any Other Name Will Still Itch as Much


The name “chickenpox” is thought to have originated in medieval England. At that time, the disease was known as “varicella,” a Latin word meaning “little pox.” The name “chickenpox” first appeared in print in 1767 in a book called The Natural history of the human race by British physician Francis Adams.

In 1804, English physician Thomas Waterhouse gave the disease its official medical name, varicella-zoster. The ”zoster” part comes from the Latin word for “girdle,” referring to the characteristic rash of chickenpox, which typically encircles the body.

However, the name “chickenpox” is still more commonly used than the medical term. It’s unclear how the name came to be associated with the disease, but one theory is that it references the fact that chickens are often affected by a similar virus. Another possibility is that it’s a corruption of the Old English word for “itch,” which was used to describe the itching sensation caused by chickenpox. Some suggest the name may be due to the small, blister-like bumps that appear on the skin during a chickenpox infection. These bumps can resemble chicken bumps, pecks, or eggs. Other theories suggest the blisters resemble chickpeas, and thus the illness became known as chickenpox. Whatever its origins, the name “chickenpox” is now firmly entrenched in popular culture.


Epidemiology of Chickenpox


Varicella is a highly contagious viral infection, and though it is often thought of as a childhood illness, it can occur at any age. The epidemiology of varicella is complex, with a wide range of cases and rates depending on age, geography, and other factors. The incidence is generally highest in young children, with rates declining in older age groups. However, the prevalence of the disease remains relatively high in adults due to continued exposure to the virus and waning immunity.

The disease remains a significant public health concern worldwide. The disease is considered both endemic and epidemic in its patterns of transmission. The incidence of varicella varies widely from year to year, but the overall rate of the disease has been declining in recent decades. However, the prevalence remains high in many parts of the world, with an estimated 10 million cases occurring yearly. VZV also remains a significant public health problem due to its potential for complications and its impact on quality of life.


How It Is Spread


Specifically, the varicella-zoster virus is the cause of both varicella (chickenpox) and varicella-zoster (shingles). The varicella-zoster virus (VZV) can remain dormant in the body for many years after the initial infection has resolved. Reactivation of the virus can occur years later and result in a condition known as herpes zoster or shingles. The risk of developing shingles increases with age, and the condition can cause long-term pain even after the rash has cleared.

The chickenpox virus is highly contagious and can spread through coughing, sneezing, or direct contact with an infected person. In fact, it is most commonly spread through contact with respiratory secretions or direct contact with the blister fluid of an infected individual. The virus replicates at the site of entry in the nasopharynx and regional lymph nodes.

Primary viremia occurs 4 to 6 days after infection and disseminates the virus to other organs, such as the liver, spleen, and sensory ganglia. This is followed by a secondary viremia with a viral skin infection. Once a person has been exposed to the virus, it typically takes 10-21 days for symptoms to appear.

Chickenpox is characterized by a rash of itchy blisters that cover the body. The illness usually lasts for about a week, and most people recover without any complications. However, varicella can be more severe in infants, adults, pregnant women, and people with weakened immune systems.

A vaccine is available to help prevent varicella, and a vaccine is also available to prevent shingles. Prompt treatment can help to speed recovery and lessen the severity of symptoms. There was a time in history, however, when phenomena called “pox parties” were all the rage.

It’s a Pox Party


A pox party is when a group of people with chickenpox get together to intentionally infect themselves or others with the varicella virus. These parties were filled with people who had varicella or other viruses. They would socialize in close contact to intentionally contract the diseases and develop immunity.

This was most commonly seen during outbreaks of varicella-zoster virus or chickenpox. Although the practice of pox parties has largely died out, there is some evidence that they may have started as early as the Middle Ages.

The rationale behind pox parties is that it is better to get the disease at a young age when it is usually milder and more manageable. In addition, developing immunity through natural infection is often seen as preferable to vaccines. However, there are risks, such as serious complications like pneumonia, encephalitis, or even death.




Since varicella is spread through respiratory droplets and contact with infected skin lesions, it is no surprise that diagnosis sometimes relies on the appearance of these blisters and the characteristic rash. However, diagnosing varicella can be challenging due to the similarity of symptoms to other viral infections such as measles or rubella. Moreover, the varicella rash can vary greatly in appearance, from a few scattered lesions to hundreds of lesions all over the body. Sometimes, a healthcare provider may order a laboratory test to confirm the diagnosis.

See a healthcare provider if you or your child develop any symptoms suggestive of varicella. Early diagnosis and treatment can help to prevent serious complications from developing.




The initial symptoms of varicella include fever, malaise, and a diffuse rash of pruritic vesicles. The rash typically begins on the face and trunk and spreads to the extremities. It consists of small, red bumps that turn into fluid-filled blisters. The blisters then break open and crust over. Other common symptoms include cough, coryza, and conjunctivitis.

Child with Chickenpox

In most cases, varicella will resolve without any lasting effects. it is important to be aware of the symptoms of both varicella and shingles so that you can seek prompt treatment if necessary. Varicella is usually a mild disease in children but can be more severe in adults. Serious complications from varicella are rare but can happen.




Complications from chickenpox include:

  • Secondary bacterial infections of skin lesions with Staphylococcus or Streptococcus
  • Primary viral pneumonia
  • Secondary bacterial pneumonia is more common in children younger than age one year.
  • Aseptic meningitis
  • Encephalitis
  • Diffuse cerebral involvement resulting in cerebellar ataxia
  • Reye syndrome


Others include aseptic meningitis, transverse myelitis, Guillain-Barré syndrome, thrombocytopenia, hemorrhagic varicella, purpura fulminans, glomerulonephritis, myocarditis, arthritis, orchitis, uveitis, iritis, and hepatitis.


Treatment for the Disease


Treatment for varicella typically focuses on relieving symptoms. Bed rest, plenty of fluids, and over-the-counter pain relievers can help ease the rash’s itchiness and discomfort. Antiviral medications may also be prescribed in some cases. With proper treatment, most people with varicella recover completely and experience no long-term health problems.


Prevention with a Vaccine


The best way to prevent varicella and maintain your health is through vaccines. The varicella vaccine is more than 90% effective at preventing the disease. The chickenpox vaccine is typically given to children between the ages of 12 and 15 months, with booster vaccines given at 4 to 6 years of age. Adults who have never had varicella or who have not been vaccinated should also consider getting one of the vaccines.

Two vaccines are available to prevent varicella: the varicella vaccine and the combination measles-mumps-rubella-varicella (MMRV) vaccine. These vaccines are highly effective in preventing varicella.


[1] “Global Infectious Diseases and epidemiology network,” GIDEON, [Online].


Kimberly Hazel

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