3. LEARNING OBJECTIVES
• Identify the causative agent of
POLIOMYELITIS
• Explain the structure of Polio
virus
• Describe the mode of
transmission of Polio virus
• Describe the symptoms and
prevention of Polio virus
4. Background
POLIO IS A CONTAGIOUS VIRAL ILLNESS THAT IN ITS MOST SEVERE
FORM CAUSES PARALYSIS, DIFFICULTY BREATHING AND
SOMETIMES DEATH.
Polio is also known as Poliomyelitis, Infantile polio and Polio
disease. And is Caused by a virus known as polio virus.
5. HISTORY OF
POLIO:
First outbreaks in Europe in early 1800’s
First outbreak in U.S. reported in 1843
Peaked in the U.S. in 1952
Became known as the Heine-Medin disease due
to the work of Dr. Jackob Heine and Dr. Karl
Oskar Medin.
Still a problem in Africa, India, Pakistan
and Afghanistan.
6. DISCOVERY
OF POLIO: 1840
In 1840
Jackob Heine
1890
In 1890 Karl
Oskar Medin
1909
Austrian physician Karl
Landsteiner along with
Erwin Popper
discovered the polio
virus in 1909.
17. PATHOGENESIS
Virus replicates in the pharynx and
GIT
Spread to the local lymph nodes and
then through the blood stream
(viremia) to the CNS
• In most cases (more than 99%), the viremia is
transient and clinical disease does not result.
• In the minority of cases (less than 1%), the
viremia persists and the virus enters the central
nervous system and causes paralytic polio
18. LIFE CYCLE OF POLIO
VIRUS:
The main steps in the life cycle of the
virus are following:
1. Entry in the host
2. Attachment with the host cell
3. Release of the RNA
4. Production of new virions
5. Release of new virions
6. Attack on nerve cells
19.
20. CLINICAL FINDINGS
• The range of responses to polio virus
infection includes:
• Inapparent, asymptomatic infection
• Abortive poliomyelitis
• Non paralytic poliomyelitis
• Paralytic poliomyelitis
21. CLINICAL FINDINGS
Inapparent
• Most
infections are
asymptomatic
or mild
Abortive
poliomyelitis
• Headache,
sore throat,
fever and
nausea
Non paralytic
poliomyelitis
• Aseptic
meningitis
with fever,
headache and
a stiff neck
Paralytic
poliomyelitis
• Paralysis is the
result of death
of motor
neurons
• Can lead to life
threatening
respiratory
paralysis
27. TREATMENT
No anti viral therapy is available
Symptomatic relief and respiratory support,
if needed
Physiotherapy for the affected muscle
28. Vaccination
The vaccine for the cure of
polio is available. TYPES OF
POLIO VACCINE:
• There are two types of polio
vaccine:
• Inactivated polio vaccine
• Oral polio vaccine
29. PREVENTION
• Two vaccines are available
• SALK VACCINE
• IPV
• Inactivated viruses
• Require a series of injections
• SABIN VACCINE
• OPV
• Contain 3 living attenuated strains of
viruses
• Trivalent vaccine
• Less expensive to administer
30. DISCOVERY OF POLIO VACCINE:
• In 1952-55 successfully produced the formalin-killed trivalent (all
three serotypes) that had its production and field trials Connaught
laboratories then affiliated with the university of Toronto. But this
vaccine couldn’t become the vaccine of choice.
• Another researcher Albert Sabin made the vaccine using weakened
form of the live virus. In 1957 he was ready for human trials of a
vaccine people could swallow. Soon this vaccine became the vaccine
of choice.
• Sabin’s vaccine was more effective than the Salk’s vaccine.
31.
32.
33. POLIO OUTCOMES AND THEIR RATIO
OUTCOMES PROPORTION OF CASES
No symptoms 95-90%
Minor Illness 4-8%
Non paralytic aseptic meningitis 1-2%
Paralytic polio 0.1-0.5%
spinal polio 79% of paralytic cases
bulbospinal polio 19% of paralytic cases
bulbo polio 2% of paralytic cases
35. REFERENCE
Microbiology… an introduction by
Tortora
Ch # 22
Pg= 652-654
Medical microbiology and
immunology by Levinson
Ch # 40
Pg = 284-286
http://www.endpolio.com.pk/
Life cycle of a Polio virus
http://amhistory.si.edu/polio/activities/l
ifecycle/index.htm
"Poliomyelitis Fact sheet N°114". WHO int. October 2014. Retrieved 3
November 2014.
Swiss institute of Bioinformatics. De Jesus NH (2007). "Epidemics to
eradication: the modern history of poliomyelitis". Virology. J. 4 (1): 70.
doi:10.1186/1743-422X-4-70. PMC 1947962. PMID 17623069.
