Poliomyelitis, also known as polio, is a viral infection that affects the motor neurons of the central nervous system. It has existed for nearly 6000 years and was depicted in ancient Egyptian carvings. Since 1988, global polio incidence has decreased over 99% due to vaccination efforts. Three WHO regions have been certified polio-free, while wild poliovirus types 1 and 3 still circulate in Pakistan, Afghanistan, and Nigeria. Polio is transmitted person-to-person primarily through the fecal-oral route or contaminated water. While most infections are asymptomatic, it can cause paralysis in 1 out of 200 cases. Global eradication efforts focus on routine immunization, supplementary vaccination campaigns, surveillance

1. POLIOMYELITIS
DR. HAFSA MARYAM

2. POLIOMYELITIS
 Also known as polio or infantile paralysis
 Originates from the Greek words“polio” meaning “grey” “myelon”
meaning “marrow”
 Vaccine-preventable systemic viral infection affecting the motor
neurons of the central nervous system (CNS).
 First known to have occurred nearly 6000 years ago
 Existence of poliomyelitis in ancient times depicted in Egyptian
carvings showing children with deformed leg walking with sticks.

3.  Since May 1988, global incidence of polio has decreased by more than
99%
 Three World Health Organization (WHO) regions (the Americas, the
Western Pacific, and Europe) have been certified as polio-free.
 Wild-type poliovirus 2 has been eradicated from the world.
 Wild-types 1 and 3 have been eradicated from most of the world, except
three countries
 Pakistan
 Afghanistan
 Nigeria
Global Burden

4.  Member of genus Enterovirus, Family Picornaviridae.
 Morphologically
 they are small (30 nm in diameter)
 Spherical virion
 nonenveloped (extremely resistant to most disinfectants + survives for extended periods on surfaces)
 icosahedral-shaped viruses
 possess a single-stranded, positive-sense RNA genome
 Composed of RNA genome enclosed in a protein shell (capsid).
 Three wild types of polio virus (WPV)
 Type 1 (accounts for 85% of paralytic illness)
 Type 2
 Type 3
 Infection by one confers immunity to that type only.
Polio virus

5.  Resistant to lipid solvents
 Stable at low pH
 highly resistant to inactivation by common disinfectants
 Alcohol
 cresols (Lysol)
 Poliovirus may survive in soil for weeks to months
 Soil, sewage and infected water have been shown to harbour the
virus.
 Remains viable in laboratory at
 freezing temperatures for many years
 in the cold for many months
 at room temperatures for days to weeks
Survival of poliovirus in environment
Readily Inactivated By
• dilute solutions of
formaldehyde
• free residual chlorine
• Heat
• Uv light

6.  poliovirus enters the oropharynx
 multiplies locally in the tonsils, lymph nodes of the neck, and then subsequently
in Peyer patches and small intestine.
 Incubation period 7-21 days (range 4-35 days).
 After 3 to 5 days
 virus is shed in stool
 can also be recovered from the throat swabs.
 Mild viremia may occur which may subside due to antibody formation.
 Virus may spread to CNS via bloodstream.
 Anterior horn cells of spinal cord (leading to limb paralysis)
 Posterior horn cells, motor neuron of thalamus and hypothalamus.
 Brainstem (bulbar poliomyelitis)
Pathogenesis

7. TRANSMISSION
 Humans only known natural host and reservoirs.
 Person to person transmission
 Fecal-oral route
 Contaminated food
 Contaminated water
 Droplet infection
 Oral-oral route
 In settings of high standards of hygiene

8.  Asymptomatic (72 %)
 Abortive Polio(1 out of 4)
 Flu like symptoms, sore throat, fever, tiredness, headache, nausea, stomach ache
 Paresthesia, hyperesthesia, stiff neck, backache
 Aseptic Meningitis / Non-paralytic polio (1 out of 25)
 Paralytic Poliomyelitis(1 out of 200, less than 1%)
 Most severe
 Leads to permanent disability or death
 2-10% of those with paralysis die as virus may affect muscles of respiration
 Post-Polio Syndrome (PPS)
 New muscle pain, weakness, paralysis
 Occurs in children 15-40 years after recovery
CLINICAL PRESENTATION

9.  Severe muscle pain and spasms
 Asymmetrical weakness, lower limbs affected more than upper limbs.
 Acute flaccid paralysis
 Muscle tone flaccid
 Reflexes brisk or absent
 Fasciculations
 Paresthesia in affected limb without sensory loss
 Paralysis remains for days or weeks
 Slow recovery occurs over months or years
PARALYTIC POLIO

10.  During acute attack findings are
 Fever, neck stiffness (nuchal rigidity), and a pleocytosis in the cerebrospinal fluid (CSF)
 Profound asymmetrical muscle weakness
 The initial phase is typically followed by some recovery of muscle strength, but permanent
weakness results from necrosis of anterior horn cells
 Recovery or convalescent stage (lasts 2 years)
 Gradual recovery of muscles.
 Rapid during first six months but slower thereafter.
 Residual paralysis stage (beyond 2 years of onset of disease)
 No recovery of muscle power
 Deformities are liable to occur
PARALYTIC POLIO FINDINGS

11.  Infected persons are most infectious from 7 to 10 days before and after
the onset of symptoms.
 Poliovirus persists in throat for 1 week.
 Poliovirus is excreted in the stools for up to six weeks.
 Immunodeficient patients can, in rare cases, become asymptomatic chronic
carriers of WPV and VDPV.
 All unimmunised persons are susceptible to the infection. Infants in the
first six months may have some protection from passively transferred
maternal immunity. Children younger than five years are at highest risk.
INFECTIVITY

12.  Specimen
 Stool (2 stool specimens, 24hour apart, within 14 days of onset)
 Throat/nasopharyngeal swab
 CSF
 Serum
i. Cell Culture
ii. Real-time reverse transcriptase PCR (intratypic differentiation between WPV and VDPV)
iii. Genome sequencing (to determine genotype and likely geographic origin)
iv. Serology (in known or suspected unvaccinated cases)
v. CSF analysis (non-specific findings)
LAB DIAGNOSIS

13.  All cases of Acute Flaccid Paralysis should be investigated for poliomyelitis.
 No specific treatment available for acute poliomyelitis
 All patients should be placed on bedrest in Isolation ward.
 Cases are managed supportively and symptomatically.
 ensure airway patency,
 adequate respiratory effort
 clearance of secretions
 Supportive measures are mainstay of treatment for severe cases of paralysis
 Monitor patients in anticipation of respiratory or circulatory complications
 vital signs
 swallowing function,
 vital capacity
 Pulse
 blood pressure,.
MANAGEMENT

14.  Even a single case of poliomyelitis is considered an epidemic and requires urgent action.
 In case of a confirmed polio case, an outbreak response plan will be made by experts, which
includes the administration of OPV to
 household contacts of the index case
 persons in the neighbourhood.
MANAGEMENT

15.  Reduce transmission risk by
 Provision of potable water
 improved hygienic practices
 Improved sanitation
 Immunisation
 OPV
 IPV
 Sensitive surveillance for all acute flaccid paralysis (AFP) cases
 Testing for virus in sewage water
 Both the WPV and VDPV
PREVENTION

16.  CDC recommends that children get four doses of polio vaccine. They
should get one dose at each of the following ages:
 2 months old
 4 months old
 6 through 18 months old
 4 through 6 years old
 Almost all children (99 out of 100) who get all the recommended doses of
polio vaccine will be protected from polio.
Polio vaccination

17. Polio vaccination
OPV IPV
Oral vaccine as drops Intra muscular vaccine
Live, attenuated virus Inactivated virus
Does not require trained health worker Requires a trained health worker
Risk of vaccine associated paralytic
polio (VAPP) or vaccine derived
paralytic polio (VDPP)
Does not cause VAPP OR cVDPP (circulating
vaccine derived paralytic polio)
Main preventive measure against polio Recommended in addition to OPV (does not
replace oral)
Trivalent OPV(protects against all three
poliovirus wild types 1-3)
Bivalent OPV (targets type 1 and 3 but
not type 2)
Trivalent only
Protects against all the three polio virus wild
types.

18.  OPV can result in VAPP in approximately 1 in 2.7 million doses of OPV.
 Caused by a genetic change in attenuated strain of poliovirus in the vaccine
within the intestine.
 Associated with
 Single dose of OPV in a child
 Unvaccinated/non-immune close contacts of recipient.
 Risk varies with dose and setting
 Lower risk with subsequent doses in industrialized countries
 Higher risk with subsequent dose in developing countries
 No outbreaks associated with VAPP
VACCINE ASSOCIATED PARALYTIC POLIO
(VAPP)

19.  A VDPV is a very rare strain of poliovirus.
 Genetically changed from the original strain contained in OPV.
 cVDPV (circulating Vaccine derived poliovirus)
 Has capacity for sustained circulation in environment.
 Sustained person to person transmission.
 Extremely rare
 Low vaccination coverage is major risk factor
 Can become endemic, spread in any under-vaccinated community and be imported to other countries.
 Can be stopped with 2 -3 rounds of high-quality, large-scale supplementary immunization.
 OPV must be phased out to secure a lasting polio-free world decreasing cVDPV risk
 Type 2 eradicated, shift from trivalent OPV to bivalent OPV.
VACCINE DERIVED POLIO VIRUS (VDPV)

20.  Polio is endemic in pakistan
 There were 128 WPV1 cases reported in 2019
 12 cases reported in 2018.
 13 WPV1 positive environmental samples were reported: 4 from Sindh province, two
from Balochistan province and seven from Punjab province
 Pakistan is classified by the International Health Regulations (IHR) as a state infected
with
 WPV1,
 cVDPV2 (circulating vaccine derived polio virus)
 potential risk of international spread
 WHO’s International Travel and Health recommends that
 all travellers to polio-affected areas be fully vaccinated against polio.
 Residents (and visitors for more than 4 weeks) from infected areas should receive an
additional dose of OPV or inactivated polio vaccine (IPV) within 4 weeks to 12 months of
travel.
Polio status of Pakistan

21.  There are four pillar of GPEI
 Routine immunization
 Supplementary immunization
 Surveillance
 Targeted ‘mop-op’ campaigns

22. ROUTINE IMMUNIZATION
 In polio-endemic countries and those with high risk for
importation and subsequent spread of poliovirus
 WHO recommends
 bOPV birth dose (zero dose)
 primary series of 3 bOPV doses
 at least 1 IPV dose.
 Benefits of zero dose
 maximize seroconversion rates following subsequent doses
 induce mucosal protection.
Zero dose At birth
1 6 weeks
2 10weeks
3 14weeks

23. SUPPLEMENTARY IMMUNIZATION
 Mass immunization campaigns
 Also known as national immunization days (NID)
 Intended to complement – not replace – routine immunization.
 aim of mass campaigns is to interrupt circulation of poliovirus by
immunizing
 every child under five years of age
 With two doses of oral polio vaccine
 regardless of previous immunization status
 3-5yrs of NIDs are required to eradicate polio
 More time required in countries with low routine immunization
coverage.
 Conducted in two rounds, one moth apart.
 Synchronized NID are being conducted along borders of Pakistan and
Afghanistan.

24.  Surveillance for all cases of Acute Flaccid Paralysis.
 Reporting
 Laboratory testing
 Environmental surveillance
 Monitoring environmental specimens supposedly contaminated by human feces.
 Poliovirus infected people shed the virus for several weeks in feces.
SURVEILLANCE OF POLIO:

25.  door-to-door immunizations
 carried out in specific areas where
 virus is known or suspected to still be circulating
 Priority aeas:
 where polio cases have been found over the previous three years
 where access to health care is difficult
 high population density
 high population mobility
 poor sanitation
 low routine immunization coverage.
Targeted ‘mop-op’ campaigns

26. Pakistan Polio Eradication Initiative has been implementing the
National Emergency Action Plan (NEAP) for Polio Eradication
2018-2019 in order to reach every child in Pakistan with the
polio vaccine and stop poliovirus circulation.

27.  Large scale supplementary immunization activities
 Working closely with EPI to improve routine immunization
 Coordinating with Afghanistan with main focus on high risk mobile
population between the two countries.
 Addressing misconceptions and building trust and demand for polio
vaccination.
 Ensuring peak performance and accountability at every level
National emergency action plan (2018-
2019)

28.  Global eradication of polio is imperative else the threat of an outbreak will hover forever.
Polio Eradication: