This presentation is prepared as part of the Course assignment of " EPI 521: Epidemiology of Disease and Health Problem" for the Master's Degree of Public Health (MPH), Pokhara University and can be used as reference materials for Poliomyelitis Disease

1. Epidemiological Perspective
of Poliomyelitis
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Presenter:
Jagat Prasad Upadhyay
MPH 2nd Semester
School of Health and
Allied Sciences (SHAS)

2. Presentation Outline
• Background
• Distribution of Disease
• Epidemiological Determinant
• Prevention and control measures
• Government Response
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3. Background
Enterovirus (RNA)
Three serotypes: type 1, type 2, type 3
Immunity to one serotype does not produce
significant immunity to other serotypes
Rapidly inactivated by heat, formaldehyde,
chlorine, ultraviolet light
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4.  First described by Michael Underwood in 1789
 Developed countries in Northern Hemisphere
suffered increasingly severe epidemics in the first
half of the 20th century
 More than 21,000 paralytic cases reported in the U.S.
in 1952
 Last case of wild poliovirus acquired in the U.S. was
1979
Background
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5. Poliomyelitis Eradication
• Mid-1950s—Widespread use of poliovirus vaccine
• 1988—Polio paralyzed ~350,000 individuals per year in more than 125
countries
• 1994—Western Hemisphere free of indigenous wild poliovirus
• 2015—Type 2 wild poliovirus eradicated
• 2019—Type 3 wild poliovirus eradicated
• 2019—Only 125 cases caused by wild poliovirus globally (99% reduction
from 1988) and endemic in only two countries
• 2019—Low routine immunization and poor vaccination campaigns resulted
in re-emergence of type 2 VDPV
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6. Epidemiological Determinant
Agent
Genus: Entero virus
Species: Polio virus
Structure: ssRNA enclosed in a protein capsid
Types: Three Types: PV1, PV2,PV3 differentiated by
the type of capsid protein.
PV1 is the most common encountered form and the one
most commonly associated with the paralysis.
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7. Epidemiological Determinant
Host: Humans are the only natural host and reservoir of
polioviruses.
Age: All age groups; children (6 months to 3 years most
susceptible) More than 95% reported in infancy and childhood
with over 50% of them in infancy.
Sex: No sex ratio differences, but in some countries, males are
infected more frequently than females in a ratio 3:1.
Risk Factors
• Unvaccinated status
• Traveling to endemic countries or regions
• Immunodeficiency
• Malnutrition
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8. Epidemiological Determinant
Environmental Factors:
• Rainy season (June to September)
• Environmental sources: food, flies and water
• Overcrowding and poor sanitation condition
Modes of Transmission:
• Since foci of infection are throat and small intestine, poliomyelitis
spread by two ways:
1. Fecal-oral routes:
• Directly spread through fingers contaminated with poliovirus.
• Indirectly spread through milk, flies, food, water and articles
2. Droplet infection
• Person to person contact with the infected person.
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9. Epidemiological Determinant
Incubation period
• 3 to 6 days for non-paralytic poliomyelitis
• 7 to 21 days for onset of paralysis in paralytic poliomyelitis
Temporal pattern
• Peaks in the summer in temperate climates; no season pattern in
tropical climates
Communicability
• Highly infectious
• Most infectious in the days immediately before and after onset of
symptoms
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10. Poliomyelitis Pathogenesis
• Entry through mouth
• Replication in oropharynx
and gastrointestinal tract
• Invades local lymphoid tissue
and may enter the
bloodstream and then infect
cells of the central nervous
system
• Destruction of motor neurons
result in distinctive paralysis.
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11. National vaccination coverage by vaccine, FY 2077/78
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12. P3CE Activities against Poliomyelitis
• Proper cleaning and disinfection of areas contacted by an
infected individual are required to prevent onward transmission
• Reinforce good personal hygiene practices
• Clean -up of kitchen and bathroom surfaces and fixtures used by
the case during their infectious period
• Using a chlorine-based solution, to prevent the spread of viruses
Prevention
• Provide information and awareness about poliomyelitis
• Provide education and awareness about vaccination
• Set of policies and exposure control plans
• Nutritious balanced and wholesome food consumption
Promotion
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13. P3CE Activities against Poliomyelitis
• Universal vaccination in early childhood is the most
effective means of preventing and eradicating
poliomyelitis
• Catch-up immunization is also recommended for
unimmunized or partially immunized adults at risk of
exposure, such as those travelling overseas and healthcare
workers in possible contact with polio cases
Protection
• Transmission Control; Breaking chain of transmission.
• Case Identification in Endemic areas
• Provision of clean water, improved hygienic practices and
sanitation are important for reducing the risk of
transmission in endemic countries.
Control
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14. P3CE Activities against Poliomyelitis
• Encourage the communities to Reinforce good
personal hygiene practices
• Encourage the community and health workers to
achieve full coverage of vaccine against polio
• Involvement of Media for Public Awareness
Encouragement
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15. Pillar for Polio Eradication
• Routine Immunization
• Supplementary Immunization
• Surveillance
• Targeted “mop-up” campaign
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16. Government Response
• Achieved and maintained high quality AFP surveillance for polio
eradication.
• Provides a reliable surveillance network for AFP, measles, acute
encephalitis syndrome and neonatal tetanus
• Extensive network of reporting units
• Supplementary immunization activity
• Acute flaccid paralysis eradication
• "Polio Free Country' Declaration
• Requirement of polio vaccination certificate
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17. Goals of the Polio Endgame Strategy 2019–2023
• Interrupt transmission of all wild poliovirus (WPV)
• Stop all circulating vaccine-derived poliovirus (cVDPV) outbreaks within
120 days of detection and eliminate the risk of emergence of future VDPVs
Goal One:
Eradication
• Contribute to strengthening immunization and health systems to help
achieve and sustain polio eradication
• Ensure sensitive poliovirus surveillance through integration with
comprehensive vaccine preventable disease (VPD) and
communicable disease surveillance systems
• Prepare for and respond to future outbreaks and emergencies
Goal Two:
Integration
• Certify eradication of WPV
• Contain all polioviruses
Goal Three:
Certificates
and
Containment
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18. Polio Eradication Strategy 2022–2026 strategic framework
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19. Thank You
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