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Transcript of Polio
Overview of Polio
Highly infectious viral disease
Severe cases can lead to paralysis or death
Has been countless Polio epidemics throughout history
No specific cure for Polio, though there are vaccines
Causes and Symptoms
Course of Infection
History and Concerns of Vaccination
The Cutter Incident
In 1955 Cutter Laboratory mistakenly distributed 120,000 injected doses of vaccine with live polio virus
Resulted in 40,000 cases of polio and 10 deaths
One of the worst pharmaceutical disasters in US history
By Kevin Wu
Later in 1962, Albert Sabin developed an oral vaccine for Polio, which can be ingested as a sweet liquid or sugar cube instead of injected as a shot
This version instead contained a weak live Polio virus
After his vaccine was licensed, Albert Sabin stated (1986), "his vaccine was superior to Salk's, because it allowed for passive immunity and would grant wider protection of the community from the deadly Polio virus"
For many decades, the cheaper and more 'child friendly' oral vaccine were used, until.....
During 1952, there was a huge surge in Polio cases in America, with 21,000 cases of paralytic poliomyelitis
In 1955 the first polio vaccination was developed by Jonas Salk, consisting of a injected dose of the dead polio virus.
Polio ravaged Americans quickly began utilising Salk's vaccine, until disaster struck...
History and Concerns of Vaccination
David Salamone's story
David possesses an immune disorder that severely weakened his immune system
By ingesting the oral vaccine, he contracted Polio from the live, weakened Polio virus
His story and many others forced the injected vaccine to be used once again in America from 1999 onwards
Roosevelt afflicted with Polio
Easily spread through contact with infected people. ie from coming in contact with tiny amounts of faeces or droplets from infected person's throat
Also spread from consuming contaminated water or food
1 in 10 infected will have symptoms like nausea, fever and vomiting
1 in 200 suffer from muscle contractions, which may lead to permanent paralysis, 20% of those die from inability to breath
Polio virus binds with CD155 receptor
Inserts its RNA, causing the cell to replicate the virus
Cell lysis, revealing hundreds of newly created polio viruses.
Polio virus is able to replicate in this fashion very quickly, overwhelming the host organ before a immune response can occur.
New Polio viruses travel down the gastrointestinal tract and can survive in the highly acidic conditions there, allowing it to infect more cells uninhibited
Route to Paralysis
In very rare cases, the virus may enter the bloodstream through damaged blood vessels
Virus spreads, reaching the Central Nervous System, and infects neurons, destroying them
Results in paralytic poliomyelitis
Polio virus enters via the mouth or nose and....
Immune Response to Polio
Similar to most viral infections, the body can defend itself against the Polio virus
Immune response consists of 2 non-specific lines of defence and 1 specific line of defence
Importance of Vaccination
Polio is almost non-existent in most Western countries due to high rates of immunisation
However Polio is still highly infectious and prevalent in a few third-world nations
It's possible to contract the virus while in those countries or from people who have traveled there
Even as a carrier, you can spread this disease to others and endanger lives
Being immune through vaccination and having a strong herd immunity, can prevent this harmful chain of infections
According to the World Health Organisation (2011) "as long as even one person remains infected somewhere in the world, all countries are at risk"
A theory that proposes the transmission of an infectious disease is less serious when large numbers of people are immune
The greater the percentage of immunised people, the smaller the chance of a susceptible person coming into contact with the polio virus from an infected individual
Immunity towards the Polio virus can be achieved through vaccination
By inserting a dead or severely weakened live polio virus into our body, it allows our immune system to easily combat it
Once the virus is destroyed, memory cells for the polio virus are created
These cells allow the body to swiftly recognise the virus and create the necessary antibodies to quickly deal with it
Thus 'immunity' is created
By injecting the Polio vaccine with a live virus, the weakened virus can spread
Surrounding people without vaccinations can contract the virus, fight it off and also become immune
Known as 'passive immunity' and allows greater herd immunity
B cells produce specific antibodies that attach themselves onto the antigens of the virus to prevent replication
These attached antibodies allow phagocytes to consume the virus
Creating a Vaccine
3rd Line: Antibodies
Upon entering through the nose or the mouth, the Polio virus will be trapped by mucus and nasal hairs and directed out of the body.
However by swallowing the mucus, these viruses may still proceed deeper into our body
1st Line: Mucus and Hairs
Phagocyte receptors bind to the antigens of the Polio virus, allowing them to engulf the virus
Natural Killer (NK) cells detect cells infected by the Polio virus, release cytokine signaling molecules and destroy the target cell
2nd Line: Phagocytes and Natural Killer Cells
After successfully destroying the Polio virus, memory B and T cells are formed
Allows an immediate specific response and antibody production whenever the virus is detected again, granting immunity
Polio — Timelines — History of Vaccines. 2014. [ONLINE] Available at: http://www.historyofvaccines.org/content/timelines/polio. [Accessed 10 July 2014].
The Cutter Incident: How America's First Polio Vaccine Led to a Growing Vaccine Crisis. 2014. [ONLINE] Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1383764/. [Accessed 10 July 2014].
David Salamone Polio | Polio vaccine comes full circle - Baltimore Sun. 2014. [ONLINE] Available at: http://articles.baltimoresun.com/1999-03-16/news/9903160091_1_polio-vaccine-oral-vaccine-sabin-vaccine. [Accessed 10 July 2014].
Etiology and General Information
Issues concerning Vaccination
Course of Infection and Immune Response
Achieving Immunity and Importance of Vaccinations
Global Polio Eradication Initiative. Oral Polio Vaccine. 2014. [ONLINE] Available at: http://www.polioeradication.org/Polioandprevention/Thevaccines/Oralpoliovaccine(OPV).aspx. [Accessed 7 July 2014].
What is a vaccination and how does it work? - Vaccine Safety - Public Health Agency of Canada. 2014. [ONLINE] Available at: http://www.phac-aspc.gc.ca/im/vs-sv/vs-faq01-eng.php. [Accessed 7 July 2014].
Community Immunity ("Herd Immunity") | Vaccines.gov. 2014. [ONLINE] Available at: http://www.vaccines.gov/basics/protection/. [Accessed 12 July 2014].
Immune-System Related Disease: Polio . 2014. [ONLINE] Available at: http://www.bio.davidson.edu/Courses/Immunology/Students/Spring2003/Holmberg/POLIO.htm. [Accessed 4 July 2014].
NMAH | Polio: How the Poliovirus Works. 2014. [ONLINE] Available at: http://amhistory.si.edu/polio/virusvaccine/how.htm. [Accessed 4 July 2014].
First Line of Defence - Non-specific barriers. 2014. [ONLINE] Available at: http://tle.westone.wa.gov.au/content/file/969144ed-0d3b-fa04-2e88-8b23de2a630c/1/human_bio_science_3b.zip/content/004_internal_defence/page_03.htm [Accessed 5 July 2014]
Poliomyelitis . 2014. [ONLINE] Available at: http://www.health.nsw.gov.au/Infectious/factsheets/Pages/Poliomyelitis.aspx. [Accessed 1 July 2014].
Disease Profiles | Jabbed on SBS. 2014. [ONLINE] Available at: http://www.sbs.com.au/shows/Jabbed/about/page/i/13/h/Disease-Profiles/. [Accessed 1 July 2014].
Polio - body, last, viral, contagious, causes, What Is Polio?. 2014. [ONLINE] Available at: http://www.humanillnesses.com/Infectious-Diseases-My-Si/Polio.html. [Accessed 2 July 2014].
SBS On Demand | Unlimited TV & Movies When You Want | Streaming TV - Jabbed - Love, Fear And Vaccines. 2014. [ONLINE] Available at: http://www.sbs.com.au/ondemand/video/30004803525/Jabbed-Love-Fear-And-Vaccines?utm_source=Lead-Marquee. [Accessed 29 June 2014].
Polio: Types, Causes, & Symptoms. 2014. [ONLINE] Available at: http://www.healthline.com/health/poliomyelitis#Overview1[Accessed 2 July 2014]