Chickenpox Varicella Zoster Virus
Science Microbes and Disease Project
# Section 1: The Microbe and the disease
MICROBE TYPE: VIRUS
» What is a Virus?
- A virus is extremely small and does not have a cell.
- It can only be seen by a microscope.
- It is composed of a protein shell with DNA inside, but without actual living parts.
- They are generally transmitted by close contact with an infected person.
Viruses act like living creatures. They hijack cells of living organisms in order to replicate themselves and spread.
»» SCIENTIFIC NAME: VARICELLA ZOSTER VIRUS (VZV)
- Viruses are classified according to their chemical, physical and morphological properties.
- Varicella Zoster Virus (VZV) is one of eight herpesviruses that infect humans.
- VZV is also known as chickenpox virus, varicella virus, zoster virus, and human herpesvirus type 3 (HHV-3).
- Normaly causes chickenpox in children, teens and young adults and herpes zoster (shingles) in adults.
»» Let's take a closer look at the structure of the VZV
Figure 1. Varicella zoster virus under electron microscope
Figure 2. Structure of the varicella zoster virus particle.
Figure 3. An icosahedron, the shape of the nucleocapsid
»» VZV is composed of 4 main parts:
- Lipid envelope: is the outer covering of the virus, with spiky glycoproteins, that allow the virus a gateway into its host.
- Tegument: is the next layer composed of viral proteins.
- Nucleocapsid: it is a protein shell with geometrical shape (a twenty-faced icosahedron), that contains DNA.
- Core: is the lifeline for the virus, with genetic information inside, only to be released when infecting a host cell.
Of all the types of herpesvirus, VZV contains the smallest genome. (http://study.com/academy/lesson/chicken-pox-virus-structure-and-function.html)
» Chickenpox: a brief history
- Chickenpox has likely been a human disease for thousands of years.
- There is suggestive evidence of chickenpox in ancient Babylonia more than 2,000 years ago.
( in http://zailiefde.blogspot.pt/2012/03/chicken-pox-history.html)
- Giovanni Filippo (1510-1580) of Palermo was the first to identify the disease.
- In the 17th century, the disease got its name from an English physician named Richard Morton, when he thought it was a milder form of smallpox.
- In 1767, William Heberden, another English physician, became the first person demonstrated that smallpox was different from chickenpox.
«THESE POCKS BREAK OUT ON MANY WITHOUT ANY ILLNESS OR PREVIOUS SIGN»
- Heberden showed how chickenpox was a mild disease and proved that a person who has had chickenpox remained immune.
- Later, in 1875, Rudolf Steiner discovered that chickenpox was caused by an infectious agent. He took some fluid from the chickenpox blisters of an infected person and scrubbed it on the skin of healthy volunteers. Sooner they also developed the symptoms.
- In 1909, Von Bokay suggested that chickenpox and shingles were related infections. This idea was confirmed between the 1920s and 1930s, when children injected with fluid from zoster vesicles got chickenpox.
- In 1972, Dr. Michiaki Takahashi developed a VZV vaccine by weakened live versions of the virus in animal and human cells. It was first used in Japan and Korea in 1988, and became available in the U.S. in 1995, and in Portugal in 2003.
# Section 2: How the microbe is spread
Chickenpox spreads easily. It is one of the most that contagious virus.
»» Transmission
- VZV can be spread:
- in the air when an infected person coughs or sneezes;
- if an infected person touches you;
- by touching or breathing in the virus particles that come from chickenpox blisters;
- from mothers with the disease to their babies (in their tummy or newborn baby).
Scratching the itchy lesions may also send virus into the air and infect unsuspecting people.
»» Preferred Method of Attack
Chickenpox is an "air and surface" attacker. The cough or sneeze of an infected person sends droplets into the air and onto surfaces.
After infecting someone, chickenpox goes underground, hiding in nerve cells . Then, it can come back years later and cause a really painful disease called shingles.
»» Symptoms
These symptoms mean that our immune system knows something is wrong...
- Chickenpox can sneak in without any symptoms.
- Or it sneaks in disguised as a cold.
- Sooner it stamps a red, itchy rash of blisters, usually showing up first on the face and chest.
- Then it adds high fever, and blisters spread over the rest of the body.
- In severe cases, blisters even show up in the mouth and ears.
- Chickenpox most commonly lasts about 5-10 days.
# Section 3: Prevention and Treatment
Antibiotics only work against bacteria, not viruses. So the best way to prevent chickenpox is to get the chickenpox vaccine
»»Vaccination
- Chickenpox vaccine is very safe and effective at preventing the disease.
- Most people who get the vaccine will not get chickenpox.
- If a vaccinated person does get chickenpox, it is usually mild (fewer blisters and mild or no fever).
- The chickenpox vaccine prevents almost all cases of severe disease.
»» How our immune system reacts after vaccination
The vaccine do not cause the disease, but it prompt immune systems to produce antibodies.
How the THE IMMUNE PLATOON works!
- Weak form of VZV invade our bodies;
- White blood cells start to make antibodies that kill the microbe;
- Our immune system recorded these antigens;
- Now with vaccination we became immune without getting chickenpox.
»» Treatment at home
- Simple treatments can usually ease fever (Ben-u-ron) and itchiness (Caladryl) caused by chickenpox.
- Zovirax can help shorten the varicella infection, and it may be appropriate for people who are at risk of developing a more serious illness.
- Keeping fingernails short may help prevent skin infections caused by scratching blisters.
- Scratching may cause a skin infection because bacteria hide beneath the fingernails.
- Scratching also increase the chances of developing a scar.
# Section 4: Curiosities
- The word is related to an old English word, "giccin" meaning "itching".
- The disease was described as "no very great danger" and as "a chicken version of the pox".
- In the medieval period, the word "pox" meant "curse". For this reason, people look at the disease as a plague that had cursed their children.
# Section 5: Sources of Information
- https://en.wikipedia.org/wiki/Varicella_zoster_virus
- http://www.cdc.gov/chickenpox/about/index.html
- http://study.com/academy/lesson/chicken-pox-virus-structure-and-function.html
- https://contagions.wordpress.com/2014/05/27/the-spotty-history-of-chicken-pox/
- https://docs.google.com/a/oparque.com/document/d/1PY26w74x7AIj1wAsth_41T92CEnHQocLA3g0cKep_Wg/edit?usp=sharing&pli=1
- https://docs.google.com/a/oparque.com/document/d/1WzVJ37DbvaO53SNpUI8H1PLEInGAUHOGxYgmT6MXL0E/edit?usp=sharing&pli=1
- http://www.healthaliciousness.com/blog/How-Your-Immune-System-Works-A-Cartoon-Story.php
- http://www.historyofvaccines.org/content/checking-chickenpox