2. Specific Learning Objectives
1. What is poliomyelitis
2. How it originates (History)
3. Problem statements World & India
4. Epidemiology of poliomyelitis
5. Prevention
6. Eradication of polio
7. AFP Surveillance
3. Poliomyelitis
• Polio is an acute viral infectious disease
contracted predominantly by children that can
lead to acute flaccid paralysis and can ultimately
cause death by paralyzing the respiratory
muscles.
• Sir Walter Scott’s was the first recorded
poliomyelitis case.
4.
5. HISTORY OF POLIO
First Known
Description Of
Polio By UNDER
WOOD.
1789
First Epidemic Of
Polio In The Island
Of St. Helena.
1834
First Description
Of Pathological
Process Involved
In Polio By
DUCHNNE.
1855
Transmission Of
Polio To Monkey
By LAND
STEINER.
1908
Growth Of Virus
By Tissue
Culture.
1949
Three Types Of
Polio Virus
Isolated And
Identified.
1951
First Large-scale
Trial Of Salk
Vaccine By
Injection.
1954
First General Use
Of Sabin Vaccine
By Mouth.
1958
Sabin OPV
vaccine replaced
Salk IPV for
easier
administration
and less expense
1962
6. HISTORY OF
POLIO
• In 1988, WHO started the global
polio eradication initiatives,
which led to the decline of polio
cases globally, i.e., from 3,50,000
cases in 1988 in more than 125
countries to 15 cases in the
endemic countries in 2018 as per
WHO report.
7. Problem Statement- World
IN WORLD-
• In 1988- 3,50,000 cases in 125 Countries.
• In 2012- 299 cases in 7 Countries.
• In 2018- 33 cases.
80% of World population is now residing in Polio Free Certified Region.
Only 2 Countries continue to report indigenous polio transmission.
• Pakistan
• Afghanistan
8. Problem Statement- India
• India successfully stopped polio transmission From January 2011.
• No natural case reported since 13th January 2011 and was declared polio free in
January 2014.
• No cases were reported due to Type 2 and Type 3 strain since 1999 and 2012,
respectively.
• Vaccine Derived Polio Virus(VDPV) type 2 was found in sewage collected in
Hyderabad and Rengareddy Districts of Telangana State during May - June 2016.
• Door to door Immunization activities.
• Active Surveillance for cases of Acute Flaccid Paralysis was done and no children were to
be found to be affected.
10. Agent
Factor
• The causative agent is the poliovirus belonging to
Enterovirus of Picornaviridae family, which has
three serotypes 1,2 and 3 .
• Most outbreaks of paralytic polio are due to type- 1
virus.
• In a cold environment. it can live in water for 4
months and in faeces for 6 months.
• Poliovirus cannot survive for long periods in the
external environment.
• The virus may be rapidly inactivated by
pasteurization , and a variety of physical and
chemical agents.
11. Agent
Factor
(B) RESERVOIR OF INFECTION : Man is the
only known reservoir of infection . Most
infections are subclinical.
(C) INFECTIOUS MATERIAL : The virus is
found in the faeces and oropharyngeal
secretions of an infected person.
(D) PERIOD OF COMMUNICABILITY : The
cases are most infectious 7 to 10 days before
and after onset of symptoms. In the faeces, the
virus is excreted commonly for 2 to 3 weeks,
sometimes as long as 3 to 4 months.
12. Host
factors
A. AGE : -The most vulnerable age is between 6
months and 3 years.
B. SEX : Sex differences have been noted in the ratio of
3 males to one female.
C. Risk factors: Unvaccinated children,
immunodeficiency, malnutrition, travelling to
endemic area
D. Immunity: Maternal antibodies are protective until
six months of age-this protection gradually
disappears.
13. Environmental
factors
1. Polio is more likely to occur during the rainy
season.
2. Approximately 60 per cent of cases recorded
in India were during June to September.
3. The environmental sources of infection are
contaminated water, food and flies .
4. Polio virus survives for a long time in a cold
environment.
5. Overcrowding and poor sanitation provide
opportunities for exposure to infection.
14. Mode of
transmission
A. FAECAL-ORAL ROUTE : This is the main
route of Spread in developing countries. The
infection may spread directly through
contaminated fingers where hygiene is poor,
or indirectly through contaminated water.
milk, foods, flies and articles of daily use.
B. DROPLET INFECTION : This may occur
in the acute phase of disease when the virus
occurs in the throat. Close personal contact
with an infected person facilitates droplet
spread. This mode of transmission may be
relatively more important in developed
countries where faecal transmission is
16. Prevention
• Immunization is the sole effective means of preventing poliomyelitis.
• Both killed and live attenuated vaccines are available, and both are
safe and effective when used correctly.
• It is essential to immunize all infants by 6 months of age to protect
them against polio.
• Two types of vaccines are used throughout the world; they are :
1. Inactivated (Salk) polio vaccine (IPV) .
2. Oral (Sabin) polio vaccine (OPV).
17. Difference between Salk (Killed) & Sabin(Live)
Vaccine characteristics
Salk (killed vaccine) Sabin (Live Attenuated Vaccine)
Injectable form / IM Oral form / Oral drops
Composition= 80 units
Type 1 :40 Units, Type 2 :8 Units, Type 3 :32
Units
Composition
Type 1 :3 lakhs, Type 2 :1 lakh, Type 3 : 3 lakhs
4 doses, first 3 doses with 1-2 months gap
followed by booster dose at 6-12 months gap
5 doses with 1 zero dose at birth followed by
booster dose at 6-24 months
80-90% efficient 90-100% efficient
Slow immune response Fast immune response
Short duration of protection Long lasting
No herd immunity Herd immunity present
Can precipitate paralysis Can be used safely
20. Reason
1. Potent vaccine
2. Only reservoir of infection is man
3. Virus cannot survive in environment for >48 hours
4. Availability of rapid response team.
• In 1988, World Health Assembly Resoluted to Eradicate Polio by End of the Year 2000.
• India Launched National Polio Eradication Program in the Year 1995.
21. Program Includes
• Routine immunization: To achieve and maintain high level of coverage for OPV about
85% and above.
• Pulse Polio Immunization (PPI):
i. Launched in India in 1995
ii. WHO Recommended the age group 0-5 years under Pulse Polio
Immunization.
iii. The success of PPI was seen as a reduction in cases from 35000 annually in
1995 to nil case in India
22. Program Includes
• AFP Surveillance: To identify and report all cases of acute flaccid paralysis (AFP)
• Mopping up round: mass supplementary immunization activities (SIA) are organized To
immunize all children aged 0-5 years.
• Protection of high-risk population: Children belonging to migrant population, slums,
construction sites, and brick-kilns.
23. AFP Surveillance
• Acute flaccid paralysis (AFP) is defined as sudden onset of weakness and floppiness in any
part of body in a child <15 years of age or paralysis in a person of any age in whom polio is
suspected.
• All cases of AFP among children <15 years of age should be reported and tested for wild polio
virus or VDPV within 48 hours of onset.
• In India, AFP surveillance for polio started in the year 1997 by establishing national polio
surveillance project(NPSP) in collaboration with WHO and GOI.
24. Objectives of AFP Surveillance
1. To recognize and report AFP cases at the earliest and to ensure prompt outbreak
immunization response with OPV
2. To confirm the cases of wild polio virus through isolation of virus in the stool sample
3. To measure the impact of routine immunization and PPI in India.
• All the districts in India should report AFP cases.
• AFP Rates of at least one case per 1,00,000 Population of children below 15 years of
age per year should be achieved by each districts.
• This measures the quality and adequacy of AFP surveillance.
25. Steps for
AFP
Surveillance
Inform and report the outbreak To DIO (District
Immunization officer), SMO (Surveillance medical officer)
Collect 2 stool sample
Case investigation
Active case search in the community
Outbreak response immunization
Include case in weekly report of surveillance
Sensitize health that have missed the case
26. Stool sample collection
• Two samples are collected at least 24 hours apart from suspected AFP Case.
• The results are good when samples are collected within two weeks of onset of paralysis
up to two months.
• The specimen should be of eight grams or thumb size in amount in a sterile container.
• Samples should be transported by maintaining reverse cold chain To the laboratory.
Editor's Notes
It is the mild and subclinical infections that play a dominant role in the spread of infection; they constitute the submerged portion of the iceberg. It is estimated that for every clinical case, there may be 1000 subclinical cases in children and 75 in adults.
There are no chronic carriers. No animal source has yet been demonstrated.
The disease occurs in all age groups, but children are usually more susceptible than adults because of the acquired immunity of the adult population. In developed countries, before the advent of vaccination, the age distribution shifted so that most patients were over the age of 5 years, and 25 per cent were over age 15 years. In India, polio is essentially a disease of infancy and childhood. About 50 per cent of cases are reported in infancy.
(c) RISK FACTORS: Several provocative or risk factors have been found to precipitate an attack of paralytic polio in individuals already infected with polio viruses. They include fatigue , trauma, intramuscular injections, operative procedures such as tonsillectomy undertaken especially during epidemics of polio and administration of immunizing agents particularly alum-containing DPT.
(d) IMMUNITY : The maternal antibodies gradually disappear during the first 6 months of life. Immunity following infection is fairly solid although reinfection can occur since infection with one type does not protect completely against the other two types of viruses. Type-2 virus appears to be the most effective antigen. Neutralizing antibody is widely recognized as an important index of immunity to polio after infection.
Active surveillance is done To detect circulation of polio virus by reporting all cases of AFP and investigating these cases for polio to ensure rapid response in the locality to interrupt the transmission.
