Presentation on theme: "By Brittany Simpson November 6, 2012 POLIOVIRUS. Polio was a prevalent disease world-wide in the mid-1900’s"— Presentation transcript:
By Brittany Simpson November 6, 2012 POLIOVIRUS
Polio was a prevalent disease world-wide in the mid-1900’s
In contrast, in 2011 polio is close to eradication
Polio is even closer to eradication this year
Notice complete eradication from India!
In the last six months, polio has come even closer to being completely erradicated.
Polio is transmitted through the fecal-oral route, so it can be prevented through proper hygiene.
Polio symptoms generally consist of mild flu-like symptoms
However, in 1 in 200 people it may cause severe paralysis and death
Poliovirus is a picornavirus– one of the smallest in existence- and more specifically is an enterovirus
The virus is surrounded by a capsid with an icosahedral lattice structure for stability.
Poliovirus is a positive single stranded RNA virus– this means once inside the cell it’s RNA can immediately be translated into proteins
Its genome consists of 7500 base pairs and codes for roughly 10 proteins
It codes for three major groups of proteins: Structural proteins, RNA Polymerase, and proteins of unknown function.
The virus enters the cell by either active pinocytosis or penetration into the plasma membrane.
Once inside the cell, the capsid is removed and proteins are processed that shut down transcription of infected cell.
The positive stranded RNA replicates and makes a negative strand to make further copies from.
The positive stranded RNA replicates and makes a negative strand to make further copies from. These copies are incorporated into newly created virions in the cell.
Once the virions have been produced, the cell undergoes lysis to release the infectious virions to infect other cells in the body
Poliovirus often infects nerve cells which can lead to paralysis and eventually death Acute-Polio2-200x1024.jpg
Jonas Salk began working in the early 1950’s to create a vaccine for the virus that would be effective against all three strains
Poliovirus is especially difficult to deactivate but it can be done by using extremely high temperatures, alkaline pHs, and certain chemical compounds
Salk used Formalin, a derivative of formaldehyde to deactivate the virus while leaving its basic structure intact.
A primitive form of the vaccine was created and then tested on monkeys and a small number of human subjects– no adverse effects were seen.
Salk and his team moved on to full scale clinical trials, testing the vaccine on nearly 2 million children.
Salk and his team moved on to full scale clinical trials, testing the vaccine on nearly 2 million children. Vaccine is Released to the public April 15,
When the vaccine is introduced to the body, your immune system will create antibodies in response to the deactivated virus.
When the vaccine is introduced to the body, your immune system will create antibodies in response to the deactivated virus. Now if you were to be infected, you would experience a secondary immune response and not fall ill with the disease!
The number of cases dropped dramatically after the introduction of the vaccine!
A second form of the vaccine is later introduced by Albert Sabin which utilizes a weakened strain of the virus to be taken orally
This is more similar to the vaccines being used in modern times in developing countries.
Polio has been eradicated from almost every country in the world; it only remains in Nigeria, Afghanistan, and Pakistan.
The GPEI hopes to have the disease completely eradicated within the next two to three years, and is working to make IPV affordable in endemic countries.