POLIOVIRUS
By Brittany Simpson
November 6, 2012
Polio was a prevalent disease world-wide in the mid-1900’s
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek/Poliocasesworldwide.aspx
In contrast, in 2011 polio is close to eradication
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek/Poliocasesworldwide.aspx
Polio is even closer to eradication this year
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek/Poliocasesworldwide.aspx
Notice complete eradication from India!
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek/Poliocasesworldwide.aspx
In the last six months, polio has come even
closer to being completely erradicated.
http://www.polioeradication.org/Dataandmonitoring/Poliothisweek/Poliocasesworldwide.aspx
Polio is transmitted through the fecal-oral route, so it
can be prevented through proper hygiene.
http://www.politedissent.com/images/dec09/polio.jpg
Polio symptoms generally consist of mild flu-like symptoms
http://spcsites.com/livewellwyobraska/wp-content/uploads/2010/12/10377.jpg
However, in 1 in 200 people it may cause severe
paralysis and death
http://students.cis.uab.edu/sajayi11/poliopatient.jpg
http://2.bp.blogspot.com/_ChxfFH9ehDU/SxUHUXQxL6I/AAAaA/V9ZnXP1Hn1g/s1600/polio.jpg
Poliovirus is a
picornavirus– one of the
smallest in existence- and
more specifically is an
enterovirus
http://www.vetmed.ucdavis.edu/viruses/02-01_450.jpg
The virus is surrounded by a capsid with an
icosahedral lattice structure for stability.
http://www.cgl.ucsf.edu/chimera/experimental/hkcage/em_1f8v_small.png
Poliovirus is a positive
single stranded RNA
virus– this means once
inside the cell it’s RNA
can immediately be
translated into proteins
http://www.npspindia.org/images/Polio-Virus.jpg
Its genome consists of 7500 base pairs
and codes for roughly 10 proteins
http://education.expasy.org/images/Picornaviridae_genome.jpg
It codes for three major
groups of proteins:
Structural proteins,
RNA Polymerase, and
proteins of unknown
function.
http://www.nature.com/nm/journal/v4/n12/images/nm1298_1357.gif
The virus enters
the cell by either
active pinocytosis
or penetration into
the plasma
membrane.
http://www.nature.com/nrmicro/journal/v3/n10/thumbs/nrmicro1284-f1.gif
Once inside the cell, the capsid is removed and
proteins are processed that shut down transcription
of infected cell.
http://www.nature.com/nrmicro/journal/v3/n10/thumbs/nrmicro1284-f1.gif
The positive
stranded RNA
replicates and
makes a negative
strand to make
further copies from.
http://www.dbc.uci.edu/~faculty/wagner/cycle03.jpg
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.
http://www.dbc.uci.edu/~faculty/wagner/cycle03.jpg
Once the virions have been produced, the cell
undergoes lysis to release the infectious virions to
infect other cells in the body
http://images.fineartamerica.com/images-medium-large/cell-lysis-kathryn-elliget.jpg
http://www.sciencephoto.com/image/254451/530wm/M1320959-Cancer_cell_apoptosis,_SEM-SPL.jpg
Poliovirus often infects
nerve cells which can
lead to paralysis and
eventually death
http://www.polioaustralia.org.au/wp-content/uploads/2010/09/Degeneration-of-Nerve-cells-Neurons-duringAcute-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
http://www.achievement.org/achievers/sal0/large/sal0-012.jpg
Poliovirus is especially difficult to deactivate but it
can be done by using extremely high temperatures,
alkaline pHs, and certain chemical compounds
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.
http://3.bp.blogspot.com/-iTBrI0M9a2k/UCqLIeMxpWI/AAAQw/U2g0diO7wlA/s1600/formalin-solution.jpg
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.
http://imagecache6.allposters.com/LRG//37/3788/BE4IF00Z.jpg
Salk and his team moved on to full scale clinical
trials, testing the vaccine on nearly 2 million children.
http://schoolworkhelper.net/wp-content/uploads/2011/08/Jonas-Salk-2.jpg
http://amhistory.si.edu/polio/virusvaccine/images/imgclinical_04.jpg
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, 1955
http://schoolworkhelper.net/wp-content/uploads/2011/08/Jonas-Salk-2.jpg
http://amhistory.si.edu/polio/virusvaccine/images/imgclinical_04.jpg
When the vaccine is
introduced to the body, your
immune system will create
antibodies in response to the
deactivated virus.
http://madcatmedia.com/eureka/files/crystalStructure_Antibody.gif
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!
http://madcatmedia.com/eureka/files/crystalStructure_Antibody.gif
The number of cases dropped dramatically after the
introduction of the vaccine!
http://barlow.gresham.k12.or.us/Science/Anderson/Polio_Critical_Thinking_files/image002.jpg
A second form of the vaccine is later introduced by
Albert Sabin which utilizes a weakened strain of the
virus to be taken orally
http://www.poliosurvivorsnetwork.org.uk/archive/lincolnshire/library/gawne/images/pandcmfig1.gif
This is more similar to the vaccines being used in
modern times in developing countries.
http://www.poliosurvivorsnetwork.org.uk/archive/lincolnshire/library/gawne/images/pandcmfig1.gif
Polio has been eradicated from almost every country in the
world; it only remains in Nigeria, Afghanistan, and Pakistan.
http://globalprosperity.files.wordpress.com/2012/01/polio-immunization-360-1-1.jpg
http://vactruth.com/wp-content/uploads/2012/05/oral-polio-vaccine.jpg
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.
http://www.bt.cdc.gov/situationawareness/polio/images/GPEI.jpg