2. CONTENTS
1. What is Polio?
2. Symptoms
3. Vaccine
4. History
5. Causes
6. Risk factors
7. Prevention
3. POLIO
Poliomyelitis
Infectious virus- Genus- Enterovirus
Family- Picornaviridae
Spread easily from person to person
Viral infection that can cause paralysis and death
Destruction of motor neurons in the central nervous
system
Polio infections: Sub-Clinical, Non-Paralytic &
Paralytic
4. SUB CLINICAL FORMS
The most common Polio Infection
Approximately- 95 % of all cases
Asymptomatic and does not Central Nervous System
NON PARALYTIC
Mild symptoms without paralysis
Approximately- 1-5 % of all cases
Affects Central Nervous System
5. PARALYTIC
The most serious cases and rare
Full or partial Paralysis
Three forms of paralysis
i . Spinal polio- Affects the spinal
ii. Bubar polio- Affects brain stem
iii. Bulbospinal polio- Affects both
Post polio syndrome- Symptoms after 35 years
A TEM micrograph of poliovirus
6. Transmission
Very Contagious
Infectious Diseases
Person-to-Person
Oral- Fecal Route
Oral-Oral route
Poor Sanitation
Contaminated Water & Food
Incubation period 6 to 20 days
A blockage of the lumbar
anterior spinal cord artery
due to polio (PV3)
Poliomyelitis pathogenesis
7. Reservoirs
Humans are the only known carrier
Subclinical- asymptomatic
Infected do not know that they have the virus and spread it.
8. General Characteristics of Polio
It is very small- ranges 22 to 33 nm
Single stranded – apx 7500 nucelotides
Virus enclosed with icosahedral protein capsid.
It can survive acid pH environment
There are three serotypes of poliovirus: namely PV1, PV2 and PV3
9. Key test for Identification
A stool or pharynx sample from suspected/infected persons
Cerebrospinal fluid
Signs and Symptoms of
Disease
Non-paralytic : Fever, Sore throat, headache, vomiting, pain in limbs,
stiffness in the neck.
Paralytic: Very similar symptoms like non-paralytic; with in a week
loss of reflexes, severe muscle aches, Weakness, flaccid paralysis-
one side
Post Polio: Muscle or joint weakness and pain; exhaustion after
minimal activity; difficult to breathing; swallowing, intolerance of cold
temeparture; concentration and memory difficulties, depression etc.
10. Historical Information
1789- Michael Underwood –first record
1930- three strains were discovered
1953- Dr. Jonas Salk developed inactivated polio vaccine
1980- post polio symptoms identified
1981- Genome sequence
1999- inactivated polio vaccine replaced by oral polio vaccine
11. Case Reported in 2017
Country Wild cases
Circulating vaccine-
derived cases
Transmission Status Type(s)
Afghanista
n
14 0 endemic WPV1
Pakistan 8 0 endemic WPV1
DRC 0 17 cVDPV only cVDPV2
Syria 0 74 cVDPV only cVDPV2
Total 22 91
12. Virulence factors
Virus enters- mouth and nose
Begins replication in the throat and intestines
Poliovirus use immunoglobulin like a molecules- receptor for recognizing host
cells
CD155 hosts motor neurons allow virus to attach
After attached these virus hijacks the cell assembly- cytolysis
