CHICKEN POX varicella_zoster_virus.gif
[also known as]

What is chicken pox?

Chickenpox is a very contagious viral disease that causes an itchy outbreak of skin blisters. Chickenpox is usually acquired by the inhalation of airborne respiratory droplets from an infected host.
The chickenpox virus spreads from person to person by direct contact with fluid from broken chickenpox blisters. Chickenpox is usually a mild disease. However, in adults and children with weakened immune systems, chickenpox can cause serious complications and even death.
A vaccine is now available to prevent chickenpox.

When was is discovered?
The chickenpox virus was originally thought to be related to the much more dangerous smallpox virus, but in the early 1900s it was realized that it is not at all like smallpox. Chicken pox, or varicella, is a member of the herpes virus family of virus. That means it is related to Epstein-Barr virus which causes mono, and herpes virus which causes fever blisters

By who?
U.K London, by a man named Giovanni Filippo (1510-1580) is believed to be first to describe Varicella, commonly known as chicken pox. He is also a major figure in the history of the science of human anatomy. Subsequently in the 1600s, an English physician named Richard Morton described what he thought a mild form of smallpox as "chicken pox." Later, in 1767, a physician named William Heberden, also from England, was the first physician to clearly demonstrate that chickenpox was different from smallpox. However, it is believed the name chickenpox was commonly used in earlier centuries before doctors identified the disease.

Is this virus generally located in a specific geographic region?
Also provide some statistics about infection numbers, mortality rates, etc.

This virus is an international disease from Begin to Boston children, teens, adults all young and old are at risk if not vaccinated.


Prevention statistics:
81% of children aged 19-35 months were vaccinated for chickenpox annually in the US 2002 (National, State, and Urban Area Vaccination Levels Among Children - US, 2002, NCHS, CDC)

Prevalence and incidence statistics for Chickenpox:
Incidence (annual) of Chickenpox: 120,624 annually (1995); 46,016 annual cases notified in USA 1999 (MMWR 1999); 199.14 per 100,000 in Canada 20001

Incidence Rate: approx 1 in 2,254 or 0.04% or 120,624 people in USA [about data]

Incidence extrapolations for USA for Chickenpox: 120,624 per year, 10,052 per month, 2,319 per week, 330 per day, 13 per hour, 0 per minute, 0 per second. Note: this extrapolation calculation uses the incidence statistic: 120,624 annually (1995); 46,016 annual cases notified in USA 1999 (MMWR 1999); 199.14 per 100,000 in Canada 20001

Prevalance of Chickenpox: Almost everyone gets chickenpox by adulthood (more than 95% of Americans). Chickenpox is highly contagious. CDC estimates that 4 million cases occur each year. (Source: excerpt from Facts About Chickenpox (Varicella): CDC-OC)

Death and mortality statistics for Chickenpox:

Deaths from Chickenpox: approximately 100 deaths (CDC-OC)

Death rate extrapolations for USA for Chickenpox: 99 per year, 8 per month, 1 per week, 0 per day, 0 per hour, 0 per minute, 0 per second. Note: this extrapolation calculation uses the deaths statistic: approximately 100 deaths (CDC-OC)

Deaths from Chickenpox: Every year there are approximately 5,000-9,000 hospitalizations and 100 deaths from chickenpox in the United States. (Source: excerpt from

Society statistics for Chickenpox::

Costs for Chickenpox: estimated $918 million in 1993

Costs for Chickenpox: In the United States, the annual cost of caring for children of normal health who contract chickenpox was estimated as $918 million in 1993. (Source: excerpt from Facts About Chickenpox (Varicella): CDC-OC)

Hospitalizations for Chickenpox: approximately 5,000-9,000 hospitalizations

After routine vaccinations in the U.S.:
Nine out of 10 are immune if vaccinated with the recommended two doses
90 percent decline in number of reported cases some areas
66 percent drop in annual death rate

[Source: CDC, Public Health Agency of Canada]

Are there any major past outbreaks? Symptoms in humans infected with the virus. Are there always symptoms or does the virus stay "dormant" for periods of time?

Chickenpox (varicella) rarely causes complications, but it is not always harmless. It can cause hospitalization and, in rare cases, death. Fortunately, since the introduction of the vaccine in 1995, hospitalizations have declined by nearly 90%, and there have been few fatal cases of chickenpox. Because the chicken pox is such a contagious and viral dieses and has been around for so long, outbreaks were relatively common and even today if not vaccinated with both shots there is risk of getting contaminated by the dieses and contaminating others who aren’t vaccinated.

The best-known signs of chickenpox are:
A red, itchy rash that initially may look like insect bites
Small, liquid-filled blisters that break open and crust over
The chickenpox rash occurs in three stages. First, there are raised pink or red bumps (papules). These bumps will turn into fluid-filled blisters (vesicles). And, finally, the vesicles will crust over and scab. It's possible that all three of these stages may occur at once.
The rash may be preceded by or accompanied by:
-Abdominal pain or loss of appetite
-Mild headache
-General feeling of unease and discomfort (malaise) or irritability
-A dry cough
*Common sites for the rash include the face, scalp, chest and back. The rash can also spread across your entire body, even into your throat, eyes and vagina. New spots continue to appear for several days. In healthy children and adults, the disease is generally mild.

*How is the virus transmitted? Can it pass from human to human? Are there other animals involved in its transmission? Can the virus infect other organisms? Do other organisms actually get sick, or are they just carriers?

Chickenpox spreads from person to person by direct contact with fluid from broken chickenpox blisters or through the air by coughing or sneezing. Chickenpox is so contagious in its early stages that an exposed person who has not had chickenpox has a 70% to 80% chance of getting the disease.
After infection, the virus stays in the body for life. Although people cannot get chickenpox twice, the same virus causes shingles. A person with shingles can spread the virus to an adult or child who has not had chickenpox, and that person can develop chickenpox.
Chicken pox is caused by a virus. Viruses are very host-specific. So humans are the only carriers of this disease.

*Details about virus structure/composition. What kind of nucleic acids does it have? What is its coat/shell made of? What surface proteins does it have?

Virus Classifications
Viruses are classified into classes based on their nucleic acid constituents and their mode of propagation.
papillomavirus Wart
Warts are caused by a Papovavirus
Cold Sore
Cold sores are caused by
herpes simplex

  • Class I - double stranded DNA.
Papovavirus (warts, HPV, cervical cancer),
Adenovirus (respiratory diseases),
Herpesvirus (cold sores, genital herpes, chicken pox, mononucleosis),
Poxvirus (smallpox, cowpox)
“Varicella-zoster virus (VZV) open reading frame 29 (ORF29) encodes a single-stranded DNA binding protein. During lytic infection, ORF29p is localized primarily to infected-cell nuclei, whereas during latency it appears in the cytoplasm of infected neurons. Following reactivation, ORF29p accumulates in the nucleus. In this report, we analyze the cellular localization patterns of ORF29p during VZV infection and during autonomous expression. Our results demonstrate that ORF29p is excluded from the nucleus in a cell-type-specific manner and that its cellular localization pattern may be altered by subsequent expression of VZV ORF61p or herpes simplex virus type 1 ICP0. In these cases, ORF61p and ICP0 induce nuclear accumulation of ORF29p in cell lines where it normally remains cytoplasmic. One cellular system utilized by ICP0 to influence protein abundance is the proteasome degradation pathway. Inhibition of the 26S proteasome, but not heat shock treatment, resulted in accumulation of ORF29p in the nucleus, similar to the effect of ICP0 expression. Immunofluorescence microscopy and pulse-chase experiments reveal that stabilization of ORF29p correlates with its nuclear accumulation and is dependent on a functional nuclear localization signal. ORF29p nuclear translocation in cultured enteric neurons and cells derived from an astrocytoma is reversible, as the protein's distribution and stability revert to the previous states when the proteasomal activity is restored. Thus, stabilization of ORF29p leads to its nuclear accumulation. Although proteasome inhibition induces ORF29p nuclear accumulation, this is not sufficient to reactivate latent VZV or target the immediate-early protein ORF62p to the nucleus in cultured guinea pig enteric neurons.” http://biblioteca.universia.net/ficha.do?id=5293126

*Details about infection. Which human cells does it infect? How does infection occur? Once the virus injects its DNA/RNA into the cell, what happens? What host cell organelles are involved? What host cell enzymes are involved?


"There are two basic patterns viral cycles although there is a great deal of variations in the specifics of how the cycles
are carried out. In bacteriophages (viruses that infect bacteria), these two cycles are referred to as the lytic and
lysogenic cycles. In the lytic cycle, the virus infects its host cell. It cannot move itself or seek out the host but relies
on chance encounters. When the virus makes contact with the host cell, it will bind to the outside of the cell and will
then either penetrate the cell or inject its nucleic acid into the cell. Once the RNA or DNA is inside the cell, the host
cell will follow the directions on the nucleic acid (remember that the DNA/RNA code is universal). The information
on the viral nucleic acid is directions on how to make more viruses. Once the new viruses are made, the host cell
ruptures and the new viruses are released. The lysogenic cycle is very similar except that once the viral DNA is
inside of the host cell, the viral DNA incorporates itself into the host’s chromosome. The viral DNA will be called a
prophage as long as it is in the host chromosome. If the cell divides, the viral DNA is replicated and passed on to
both daughter cells as part of the chromosomes. At some point (there are a number of triggers that can initiate this)
the viral DNA will leave the host cell’s chromosome. At that point, the new viruses will begin to be made and the
host cell will then rupture and release the new viruses. Viruses that infect plant and animal cells will also follow
cycles similar to bacteriophage cycles. The animal or plant host cells may not rupture but instead may essentially
“leak” new viruses. If a cell is infected with a virus (and the virus is not “hidden” in the host cell’s chromosome),
the cell will not be functioning correctly as the only thing it will be doing is making new viruses. chicken pox and shingles (Varicella-zoster virus, same one causes both) is a dsDNA withc too is part of the DNA."

*How does the human body fight the virus?

white blood cells attack the pathogenic (bad) cells that cause it, and immunity B cells are released trying to bond with an antigen on the chicken pox pathogen, when it does, a signal is sent to the T cells to make antibodies once the invading pathogen is destroyed, the T, B, antibody, and a few white blood cells turn to memory cells wich will destroy the pathogen quicker before it can be more harmful it is technically possible to get it twice if you have bad immunity the chicken pox virus has mutated very little in the years, so the memory cells still have no problem destroying the invading pathogens.

*How has the virus changed over time? Are there documented cases of it mutating? How does this occur? What specific changes were observed and how did this affect humans or other organisms? If no mutations have been directly observed, predict what might happen if the virus were to change in the future.
The chicken pox’s has not mutated or matured much over the years. It satys the same. But if it were to change later in the future I think that maybe they would be less immune. It would be lke getting a cold, you can get it over and over again. Because it’s airborne I think that in the future the virus will resist the vaccine.

How is this virus treated by medical professionals? Do we have a vaccination/immunization against this virus? How can infection be prevented?

There is a vaccine for the chicken pox. The varicella vaccine is a shot that can prevent chickenpox. It is called varicella because the varicella virus causes chickenpox. Up to 90% of people who receive the vaccine will not get chickenpox. People who get chickenpox after having the vaccine have a milder form of the disease. The chickenpox vaccine is not required like some other vaccines. However, it is generally safe and will save your child from suffering with a preventable illness. Chickenpox can be prevented . The easiest way to prevent catching chicken pox is to get vaccinated. However, vaccination is only successful in 70% to 90% of all vaccinations. Individuals who have been vaccinated but still acquire chickenpox, usually have a milder disease that heals more quickly than non vaccinated individuals.