Polio is a highly infectious disease caused by an RNA virus that affects children under 5 years old. It can cause paralysis if the virus infects the central nervous system. Three types of poliovirus exist. While most infections are asymptomatic, paralysis occurs in less than 1% of cases. Transmission is primarily through the fecal-oral route. Nepal was declared polio-free in 2014 through vaccination efforts. Oral polio vaccine is effective at inducing immunity and spreading to non-immunized individuals. Maintaining high vaccination coverage is important to prevent new outbreaks.

1. Prepared by:
Narayani Tripathi
Nirmala Devkota
Nirmala Thapa
Pabitra Bastola Dawadi
Prabina Subedi
POLIOMYELITIS

2. INTRODUCTION
 Polio is a highly infectious disease caused by an RNA
virus.
 It affects usually children under 5 years of age.
 It is primarily an infection of the human alimentary tract
but the virus may infect the central nervous system in
very small percentage of cases(1%).
 It invades the nervous system, and can cause total
paralysis.

3. EPIDEMIOLOGICAL
DETERMINANTS
AGENTS FACTORS
Agent
 The causative agent is the poliovirus which has three types-1,2 and
3
 Most outbreaks of paralytic polio are due to type -1 virus
 Polio virus can survive for long periods in the external
environment ( for 4 months in water and 6 month in faeces)
Reservoirs of infection: Man is the only known reservoir of
infection. Main infection are subclinical.

4. HOST FACTORS
 Age: occurs in all age group but children are more
susceptible than adult.
 Sex : sex difference has been noted in the ratio of three
males to one female
 Immunity : maternal immunity disappear during the first
six month of the life. Immunity after the infection is life
long but reinjection can occur since the infection with
one type does not protect completely against the other
two type of infection.

5. ENVIRONMENTAL FACTORS
 Polio is more likely to occur during the rainy
season
 The environmental source of the infection are
contaminated water, food and flies
 Polio virus survive for a long time in a cold
environment
 Overcrowding and poor sanitation provide
opportunities for exposure to infection.

6. POLIOMYELITIS-GLOBAL
SITUATION
 One in 200 infections leads to irreversible paralysis. Among those
paralyzed, 5% to 10% die when their breathing muscles become
immobilized
 Polio cases have decreased by over 99% since 1988, from
an estimated 350 000 cases then, to 416 reported cases in 2013
 The reduction is the result of the global effort to eradicate the
disease.
 In 2014, only 3 countries (Afghanistan, Nigeria and Pakistan)
remain polio-endemic, down from more than 125 in 1988

7.  "Before a Region can be certified polio-free, several
conditions must be satisfied such as:
 at least three years of zero confirmed cases due to indigenous
wild poliovirus; excellent laboratory-based surveillance for
poliovirus; demonstrated capacity to detect, report, and
respond to imported cases of poliomyelitis; and assurance of
safe containment of polioviruses in laboratories (introduced
since 2000).”

8. POLIO CASES IN SEAR
 In SEAR, India is the country reporting large number of
polio cases.
 During the year 2009 a total of 741 cases of polio were
reported in India, as against 599 cases in the year 2008.
 As in previous year the majority od cases were reported
from Uttar Pardesh and Bihar.

9. Poliomyelitis- SEAR Situation
 March 27,2014: WHO declared Nepal polio-free, along
with other 10 countries, for maintaining a polio-free status -
Nepal, Bangladesh, Bhutan, Democratic People´s Republic
of Korea, India, Indonesia, Maldives, Myanmar, Sri Lanka,
Thailand and Timor- Leste
 South East Asian Region is the 4th WHO region to be
certified as Polio free

10. Situation in Nepal

12. Situation in Nepal
 The country has remained free of polio infection since September
2010.
 On August 30, a 22-month baby girl from Rautahat was the last
case to be diagnosed with polio.
 Polio got particular focus since 1996 when the government started
marking National Immunization Day.

13. TRANSMISSION
 Faecal–Oral Route: This is the main route of infection ( may
spread directly through contaminated fingers where hygiene is
poor indirectly through contaminated water, milk, food flies and
articles of daily use.
 Droplet infection: This may occur in the acute phase of the
infection when virus occurs in the throat-close personal contact
with infected person facilitates droplet spread.

14. INCUBATION PERIOD
 Usually 7-14 days

15. CLINICAL SPECTRUM
 Inapparent(Subclinical infection): This occurs approximately
in 91-96 % of poliovirus infection. Recognition only by virus
isolation or raising antibody titres.
 Minor illness: Occurs in approximately 4-8% of infection. It is
self limiting illness which recovers quickly. Recognition only
by virus isolation or raising antibody titres.

16. CLINICAL SPECTRUM
 Non-paralytic polio: occurs in about 1% of all infection.
Initial symptoms are fever, fatigue, headache, vomiting,
stiffness in the neck and pain in the limbs
 Paralytic polio: occurs in less than 1% of all infection.
The virus invades CNS and cause varying degree of
paralysis.

17. PREVENTION
 There is no cure for polio, it can only be prevented. Polio vaccine, given
multiple times, can protect a child for life
 Both killed and live attenuated vaccine are available and safe
 Vaccines:
 IPV(Inactivated polio vaccine)-Salk-do not produce local immunity or
intestinal immunity
 Oral polio vaccine-Sabin- stimulate both local and systemic immunity

18. PREVENTION
 The vaccine progeny is excreted in the faeces and secondary spread
occurs to household contacts in the community
 Non –immunized persons may therefore be immunized- “herd
immunity”
 Advantages:
 Easy to administer, inexpensive
 Induce both humeral and intestinal immunity
 Vaccines excrete virus and so infect others who are immunized
 Useful in controlling epidemic

19. NATIONAL IMMUNIZATION
PROGRAM
 Objective 3: Achieve and maintain polio free
status
 Key strategies:
 Achieve and maintain high immunity levels
against Polio by strengthening routine immunization
 and conducting high quality national polio immunization
campaigns.
 Respond adequately and timely to outbreak of
poliomyelitis with appropriate vaccine
 Achieve and maintain certification standard AFP
surveillance

21. Name of vaccines Number of
dosages
Recommended age
BCG 1 At birth or on first
contact with health
institution
OPV 3 6,10 and 14 weeks of
age
DPT- Hep B- Hib 3 6, 10 and 14 weeks of
age
Meseales-Rubella 1 9 months of age
Td 2 Pregnant women( 2
dosage)
JE 1 12-23 months of age

22. CONCLUSION
 Affecting 3-5 million people worldwide polio plays
negative impact on national growth and
development.
 The disease is most common in places with poor
sanitation, crowding, war and famine .
 As it occurs both outbreaks and chronically in
certain area such as Afghanistan, Nigeria and
Pakistan and South East, while the risk of death
among those affected is usually less than 5% it
may be as high as 50% among some groups who
don’t have access to treatment.

23. REFERENCES
 http://www.who.int/mediacentre/factsheets/fs114/
en/
 http://www.who.int/mediacentre/factsheets/fs114/
en/