Current trends in the global burden and approach to Poliovirus infection include vaccination,management and Eradication strategies

1. POLIO
DR INNOCENT A. AGABA
DEPARTMENT OF PAEDIATRICS,
MAUTH YOLA
19-07-23

2. OUTLINE
• Introduction
• Historical Insights
• Epidemiology
• Aetiology
• Pathogenesis
• Diagnostic considerations (AFP)
• Complications
• Investigations
• Treatment
• Prevention
• Eradicating Polio
• Conclusion
• References

3. INTRODUCTION
• Also known as Heine–Medin Disease; sporadic infantile
paralysis
• A disabling and life threatening disease caused by the
Poliovirus
• A important cause of Acute Flaccid Paralysis(AFP)
• Highly communicable and outbreak prone.
• Global eradication is a top priority on WHO list.

4. HISTORICAL INSIGHTS
• Egyptian paintings from the period 1403 to 1365 BC depict children
with deformed limbs, walking with sticks.
• In 1789, an English physician Michael Underwood gave the first clinical
description where he referred to polio as “debility of the lower
extremities.”
• First isolated in 1909 by Karl Landsteiner and Erwin Popper
• In the late 19th and early 20th century, frequent epidemics saw Polio
becoming the most feared disease in the world - the “wrath of God”
• During the 1970s,routine immunization was introduced worldwide as
part of national immunization programs.
• Global Polio Eradication Initiative(GPEI) was established in 1988.

7. EPIDEMIOLOGY
• One in 200 infections leads to irreversible paralysis. Among those
paralysed, 5–10% die when their breathing muscles become
immobilized.
• Almost 20 million people are able to walk today who would otherwise
have been paralysed
• Cases due to wild poliovirus have decreased by over 99% since 1988,
from an estimated 350 000 cases then, to 6 reported cases in 2021.
• Type 2 wild poliovirus was declared eradicated in September 2015. The
last detection was in India, 1999. Type 3 wild poliovirus was declared
eradicated in October 2019. It was last detected in November 2012.
Only type 1 wild poliovirus remains.
• As at 2022, endemic wild poliovirus type 1 remained in two countries:
Pakistan and Afghanistan.

8. EPIDEMIOLOGY
• The 35th meeting of the Emergency comittee under the IHR on international
spread of poliovirus convened by WHO DG on 3 may 2023 noted that;
 Wild poliovirus - Ongoing transmission in Eastern Afghanistan
- Importation of WPV1 into Malawi,Mozambique from Pakistan
- Suboptimal immunization coverage in Southeastern
African countries
 Circulating vaccine derived poliovirus(cVDPV)
-High transmission in DR Congo,Madagascar,Mozambique
- 1 case in Isreal
-27 countries including Nigeria said to be infected with cVDPV2
with or without evidence of local transmission
 117 confirmed cases of circulating variant polioviruses and 107 detections in
sampled wastewater so far in the African Region in 2023.

9. • The global effort to eradicate polio has been declared a Public Health Initiative of
International Concern.
• As of 2012, Nigeria accounted for more than half of all polio cases worldwide,
according to WHO.
• There has been no recorded case of wild polio virus since 2016. The last case was
recorded in Borno State, north-east Nigeria in 2016
• No cVDPV2 case was reported this week. There have been 16 cVDPV2 cases
reported this year and 48 cases in 2022.
• According to the WHO report of May 2023, Northern Nigeria is one of these
seven sub-national areas that now hold the key to a polio-free world.
• The virus is currently confined primarily to two states in the northwest zone of
the country, namely Sokoto and Zamfara.

12. EPIDEMIOLOGY
• Incubation period
Paralytic form : usually 7 – 14 days, with a range of 5 – 35 days
Minor illness: 3 – 5 days
Route of transmission
Faeco –oral
Pharyngeal secretions
Contaminated water
• Maximum excretion of the virus is seen in 2 to 3 days prior and 1 week
after appearance of symptoms
• Humans are the only known reservoir
Sex distribution
• Males and female children are affected with equal frequency
Age
• Children mostly between 2 and 4 years
• However, anyone of any age who is unvaccinated can contract the disease

13. AETIOLOGY
FAMILY: Picornaviridae
GENUS: Enterovirus
SPECIES: Enterovirus C
VIRUS: Poliovirus
• Non enveloped
• Single stranded RNA
• Icosahedral protein shell
• 3 SEROTYPES : PV -1,PV -2,PV -3
• Survives in water for 3 months and in faeces for 6 months
• Inactivated by heat,formaldehyde,chlorine,UV Light

15. PATHOGENESIS

16. PATHOGENESIS

17. PATHOLOGY
• Neurotropic
• Cytopathic
• Special affinity for CD155 receptors
• Infects grey matter of spinal cord, brainstem and cortex.
• Histological appearance of the affected brain cells shows
-vacuolation and infiltration.
-accumulation of plasma cells, polymorphonuclear
leukocytes and microglia.
-Petechial haemorrhage
-degeneration of Nissl bodies
-nuclear changes
-neuronal death
• Widespread muscular atrophy occurs leading to flaccid paralysis.

18. PATHOLOGY

19. PREDISPOSING FACTORS
• Non vaccinated
• Immunocompromised individuals
• Poor sanitation
• Poor socioeconomic status
• Overcrowding
• Institutional settings
• strenous physical exercise,
• Tonsillectomy
• Pregnancy

21. CLINICAL FEATURES
• 4 FORMS OF MANIFESTATIONS
Inapparent infection
Abortive polio
Non paralytic forms
Paralytic form
• 4 TYPES OF POLIOMYELITIS
SPINAL – Cervical, Thoracic, Lumbar
BULBAR – Cranial nerves, Respiratory system
BULBOSPINAL
POLIOENCEPHALITIS

22. CLINICAL FEATURES
1 Inapparent infection (90 – 95%)
• Only a primary transient viraemia ocurs and the poliovirus infection is
asymptomatic
• Mild cases characterised with non specific symptoms that usually
resolves in a few days
Fever Abdominal pain
Headache Vomiting
Nausea, Sore throat
2 Abortive Disease (4 – 8%)
• Duration usually less than 5 days
• Non specific symptoms as (1) above with Pharyngeal hyperaemia
• No neurological deficits

23. 3 Non Paralytic form(1 -2%)
• Symptoms as in (2) above followed/associated with signs of meningeal
irritation:
Generalised Myalgia
Nuchal rigidity Irritability
More severe Headache Vomitting
• LAB : The CSF shows a lymphocytic pleocytosis + a rise in protein and a
normal sugar content
4 Paralytic Polio (<0.1 – 0.5%)
Spinal : 79%
Bulbospinal : 19%
Bulbar : 2%

24. • Occurs when the virus enters the CNS and replicates in motor neurons
within the spinal cord, brainstem or motor cortex.
• Characterised by systemic manifestations in addition to (3) above:
 Compromise of motor neurons(AFP)
 Paraesthesia
 Assymetric loss of muscle function
 Swallowing difficulties, pooling of oral secretions,vocal cord palsy
 Muscle atrophy
 Respiratory arrest
 Loss of deep tendon reflexes
• Recovery : Complete,partial or absent.
• Recovery from paralysis usually begins within one week
• Patients who have recovered from poliomyelitis occasionally develop a
post poliomyelitis syndrome.

26. Post Polio syndrome
• May develop 20-40 years after infection with poliovirus
• Characterized by late deterioration in muscle bulk and power
many years after the initial infection.
• Growth in affected limb slowed down as much as 6 - 7cm by
disuse,atrophy.
• Degree of shortening depends on severity of paralysis and age
at which paralysis began.

27. RECOGNIZING POLIO

28. RECOGNIZING POLIO;
The untreated polio patient

29. DIAGNOSTIC CONSIDERATIONS
• According to WHO case defintion of AFP:
• “ANY CHILD UNDER 15 YEARS OF AGE
WITH ACUTE ONSET OF FOCAL
WEAKNESS OR PARALYSIS OR ANY
AGE WHN POLIO IS SUSPECTED”

30. Polio GBS Traumatic Neuritis Transverse Myelitis
Etiology Polio type 1,2,3
viruses
Immunologic Trauma Unknown-multiple
viruses
Onset of
paralysis
24-48hrs Few hrs -10 days Few hrs -4 days Few hrs -4 days
Fever at onset High at onset of
paralysis
Not common Before during or
after paralysis
Rarely present
Flaccid paralysis Acute asymmetric,
(proximal muscles)
Acute symmetrical,
(distal muscles)
Acute asymmetrical
(only one limb)
Acute symmetrical
involving Lower limbs
CNS involvement Only Bulbar
involvement
May Occur Absent Absent
Respiratory
insufficiency
Only Bulbar
involvement
In severe cases Absent Absent
Autonomic
nervous system
Plus Rare May be present May be present
CSF High WBC’s; Normal
to Slightly elevated
protein
< 10 WBC’s; High
Protein
Normal Normal Count;
Normal to Slightly
elevated protein
EMG (@ 3 weeks) Abnormal Normal Normal Normal
Sequelae (3 -
12mths)
Severe asymmetrical
atrophy
Variable Variable Yes

31. DIFFERENTIALS OF ACUTE FLACCID
PARALYSIS

32. DIFFERENTIALS OF AFP

33. COMPLICATIONS
• Early vs Late
• CNS -Meningitis, (Polio)Encephalitis
• MSS - Skeletal deformities,Scoliosis, Contractures
• CVS -Myocarditis
• RS - Aspiration pneumonitis, Orthostatic pneumonia,Cor Pulmonale,
Pulmonary Edema
• GUS - Nephrolithiasis,UTI
• GI - Constipation, Paralytic Ileus
• PSYCH - Depression,Low self esteem
• SOCIAL - Poor QOL, Poverty,Stigmatisation
• Outbreaks
• Economic impact

34. INVESTIGATIONS
• CULTURE
 CSF,stool,throat,blood
 Culture medium : human amnion cell line and human embryo cell line are
generally preferred methods
 If poliovirus infection is suspected, two or more fecal and throat swab samples
should be obtained at least 1 day apart and cultured for enterovirus as soon as
possible.
 If poliovirus is isolated, it should be sent to the CDC for identification as either
wild-type or vaccine virus.

35. • INTRATYPIC DIFFERENTIATION TESTS :
 ELISA,Hybridization techniques used for differentiating Wild strain from VAPP
• SEROLOGY
 Acute and convalescent antibody titers.
* Positive IgM titre in both acute and chronic infection
* 4 fold increase in IgG during convalescence
• NUCLEIC ACID AMPLIFICATION TESTS
 PCR – More rapid, sensitive and specific than Culture
• IMAGING
 MRI

36. MANAGEMENT
• No Antiviral agents are currently known to be effective against Poliovirus
• Treatment is mainly symptomatic and supportive
• Multidisciplinary approach
Early stages
Pre-paralytic Paralytic
Bed rest is imperative Mechanical ventilation
Analgesia Tracheostomy
Monitoring Physical therapy
Skin care
Bowel and Bladder care
Diet & Nutrition

37. MANAGEMENT cont…
• Late stages
 Encourage return to mild activity as soon as
possible
 Physiotherapy
 Orthopaedic measures
*Muscle and Tendon transplantation
*Arthrodesis
*Osteotomy
 Braces,Orthotics
 Occupational therapy
 Psychotherapy
 Follow up i.e the 60 day follow up examination

38. 60-day Follow up examination
• Aim: To confirm the presence or absence of residual weakness.
• Indications:
-Inadequate or no stool specimens
-Isolation of vaccine virus from stool
-Isolation of wild poliovirus from stool
-Strong suggestion of poliomyelitis on intial
examination
• Components:
- Weakness
-Assymetric skin folds
-Disparity in Left-right mid-arm/mid-thigh circumference
• Child is considered to have residual weakness if any of the above is
present,even if minimal.

39. PROGNOSIS
• Patients with inapparent or abortive poliomyelitis
recover without significant sequelae.
• Bulbar paralytic poliomyelitis has been associated
with the highest rate of complications and a
mortality rate as high as 60%, followed by spinal
poliomyelitis.
• Respiratory failure is responsible for most of the
death.

40. PREVENTION
• PRIMORDIAL TETIARY
 Policies e.g GPEI Rehabilitation
 Good political will Multidisciplinary approach
 National immunization days Support groups
• PRIMARY
• Education -Hcws,Public,travellers
 Immunisation -Routine,Supplementary,ORIs,PPIs
 Handwashing
 Hygeine
 Optimal sanitation practices
• SECONDARY
 surveillance for acute flaccid paralysis (AFP) cases
 Testing for virus in sewage water
 Rapid case investigations
 Containment of outbreaks

41. POLIO VACCINATION

42. POLIO VACCINATION
• There is no cure for polio, it can only be prevented.
• Polio vaccine, given multiple times, can protect a child for life.
• Two types of vaccine used ;
 Oral attenuated Polio vaccine (OPV) “SABIN”
*Associated with VAPP
* Herd immunity possible
• OPV is given orally as 2 drops per dose, and infants receive it at birth (OPV
0), 6 weeks (OPV 1), 10 weeks (OPV 2), and 14 weeks (OPV 3).
 Inactivated Polio vaccine (IPV) “SALK”
*Parenteral administeration
*Not as “immunogenic” as OPV
*Does not induce mucosal immunity
*Not associated with VAPP

44. Recommendations for Poliovirus
Vaccination of Adults
• Immunization is recommended for those with a higher risk of exposure than the
general population, including:
 travelers to areas where poliovirus is or may be epidemic or endemic;
 members of communities or population groups with disease caused by wild-type
polioviruses;
 laboratory workers handling specimens that may contain wild-type polioviruses;
and
 health care workers in close contact with patients who may be excreting wild-type
polioviruses.
• Three doses of IPV are recommended for adults who need to be immunized. The
second dose should be given 1–2 months after the first dose; the third dose should
be given 6–12 months after the second dose.
• Adults who are at increased risk of exposure to wild-type poliovirus and who have
previously completed primary immunization should receive a single dose of IPV
• Adults who did not complete primary immunization should receive the remaining
vaccinations with IPV.

45. ERADICATING POLIO
• Polio Eradication Strategy 2022 – 2026.
• The Global Polio Eradication Initiative is a public-private partnership
led by national governments with six partners;
 World Health Organization (WHO),
 Rotary International,
 US Centers for Disease Control and Prevention (CDC)
-Global Immunization Division (GID),
-Polio and Picornavirus Laboratory,
-Stop Transmission of Polio (STOP) teams.
 United Nations Children’s Fund (UNICEF)
-implementation of intensified National Immunization Days
(NIDs)
-Sub-National Immunization Days (SNIDs)
-mop-up campaigns
 Bill & Melinda Gates Foundation
 Gavi, the Vaccine Alliance.

46. • Other partners include:
 United Nations Foundation and other private foundations
 Development banks (e.g. the World Bank)
 Donor governments
 European Commission
 Humanitarian and nongovernmental organizations (e.g.
the International Red Cross and Red Crescent societies)
 Corporate partners (e.g. Aventis Pasteur, De Beers)
 Volunteers in developing countries.

47. • GPEI defines four pillars of polio eradication:
Routine immunization:
• High infant immunization coverage with four doses of oral polio vaccine (OPV) in
the first year of life in developing and endemic countries, and routine
immunization with OPV and/or IPV elsewhere.
Supplementary immunization:
• Organization of “National immunization days” to provide supplementary doses of
oral polio vaccine to all children less than five years of age.
Surveillance:
• Active surveillance for wild poliovirus through reporting and laboratory testing of
all cases of acute flaccid paralysis among children less than fifteen years of age.
Targeted “mop-up” campaigns:
• Targeted “mop-up” campaigns once wild poliovirus transmission is limited to a
specific focal area.

48. DRAWBACKS TO POLIO ERADICATION
IN NIGERIA
• Insurgency,forced migration,IDP camps.
• Poor coverage i.e weak healthcare systems
• Failure to reach enough children during immunization campaigns
• Religous beliefs
• Lack of good political will
• Lack of trust in polio immunization by some section of the public

49. CONCLUSION
• Polio is a highly contagious disease with long lasting
debilitating effect.
• It is vaccine preventable.
• As long as a single child remains infected, children in
all countries are at risk of contracting polio.
• Scientific data prove beyond doubt that polio
eradication will also require the eventual disuse of
OPV, otherwise there will be resurgence in a polio-
free world due to vaccine-associated paralytic polio
and polio outbreaks due to circulating vaccine-
derived polioviruses.

50. REFERENCES
• Kliegman R. M. et al, Nelson Textbook of Paediatrics. 20th ed Elsevier 2016
• Azubike JC, Nkangineme KE. Paediatrics and Child Health in a tropical region. 3rd edition,
Educational Printing Press 2016
• Heymann D, Aylward B. Polio will soon be history, Bull World Health Organ. 2007 Jan.
85(1): 7-8.
• Benjamin E; Paediatric Poliomyelitis; 4th Nov 2022: Medscape.
https://emedicine.medscape.com/article/967970 accessed on 16th July 2023
• Ian P . D et al, Davidon’s principles and practice of Medicine. 24th ed, Elsevier Ltd 2018
• “Poliovirus”. (2023, June 11th). In Wikipedia. https://en.wikipedia.org/wiki/poliovirus
• World Health Organisation. (2023) Health topics/ poliomyelitis https://who.int/health-
topics/poliomyeliis

51. •THANK YOU FOR
LISTENING