2. 1. What is Polio?
2. Symptoms
3. Vaccine
4. History
5. Causes
6. Risk factors
7. Prevention
3. POLIOVIRUS
• Poliomyelitis is an acute infectious disease that in its serious form affects
the central nervous system.
• The destruction of motor neurons in the spinal cord results in flaccid
paralysis. However, most poliovirus infections are subclinical.
4. Polio can be transferred in multiple ways and some include:
Direct person-to-person contact (NCBI, 2012)
contact with mucus or saliva from the nose or mouth (NCBI, 2012)
Contact with infected feces (NCBI, 2012)
Transmission
5. MORPHOLOGY POLIOVIRUS
• Size: The virion is a spherical particle, about 27 nm in diameter
• Capsid: It consists of a capsid shell of 60 subunits, each consisting of
four viral proteins (VP1-VP4), arranged in icosahedral symmetry.
• Genome: The genome is a single strand of positive sense RNA.
• The virus can be crystallised, and arrays of virus crystals can be seen in
the cytoplasm of infected cells.
6.
7. RESISTANCE POLIOVIRUS
1.Poliovirus is resistant to ether, chloroform, proteolytic enzymes of
the intestinal contents and detergents.
2. It is stable at pH 3.
3. In feces, virus can survive for months at 4°C, for years at –20 or –
70°C and at room temperature for several weeks,
4. They are inactivated when heated at 55°C for 30 minutes.
8. 5. Drying rapidly inactivates enteroviruses by ultraviolet
light, and usually by drying.
6. Formaldehyde and oxidizing disinfectants destroy the
virus.
7. Chlorination destroys the virus in water but organic
matter delays inactivation.
8. Poliovirus does not survive lyophilization well
11. CLINICAL FEATURES
1. Asymptomatic Illness
2. Abortive Poliomyelitis: The Minor Illness
3. Nonparalytic Poliomyelitis or Aseptic Meningitis
4. Paralytic Poliomyelitis: The Major Illness
5. Progressive Postpoliomyelitis Muscle Atrophy
13. SPECIMENS
• Blood, CSF, throat swabs and feces.
• Polioviruses may be isolated from the patient’s pharynx during the first
few days of illness, from the feces for as long as 30 days, but from the
CSF only rarely but can be obtained from the spinal cord and brain,
postmortem unlike other enteroviruses.
14. CULTURE
• Primary monkey kidney cells are usually employed.
• The virus growth is indicated by typical cytopathic effects in 2-3 days.
• An isolated virus is identified and typed by neutralization with specific
antiserum.
15. SEROLOGICAL TESTS
• Serodiagnosis is less often employed. Antibody rise can be
demonstrated in paired sera by neutralization or complement
fixation tests.
17. IMMUNISATION
SCHEDULE
• Primary course of 3 doses of OPV at one-month intervals, commencing the
first dose when infant is 6 weeks old.
• One booster dose of OPV is recommended 12 to 18 months later
