3rd year BAMS, Swasthavritta, Epidemiology of communicable diseases

1. POLIOMYELITIS
Dr. Jasminkumar Viramgami
Reader & H.O.D.,
Dept. of Swasthavritta,
Govt. Akhandanand Ayurved College, Ahmedabad, Gujarat

3. Poliomyelitis is…
• an acute viral infection
• caused by an RNA virus.
• word means “ grey spinal cord inflammation”
• primarily an infection of the human
alimentary tract
• virus may infect the CNS in about 1 % of cases
• resulting in varying degrees of paralysis, and
possibly death.

4. Problem statement
• In the pre-vaccination era,
poliomyelitis was found in
all countries of the world.
• The extensive use of polio
vaccines since 1954
eliminated the disease in
developed countries.
• India has not reported any polio case since
January 2011, and has been declared polio-
free since 27th March 2014.

5. Agent factors
AGENT : poliovirus
• three serotypes 1,2 and 3.
• paralytic polio outbreaks
mostly due to type-1 virus.
• faeco-oral route transmission.
• can survive for long periods in the external
environment.
• rapidly inactivated by pasteurization, and a
variety of physical and chemical agents.

7. Epidemiological Characteristics of
Polio Serotypes
• All types cause paralysis
• Type 1- Most frequent paralysis,
Highest epidemic potential,
During polio free last serotype to disappear
• Type 2- Rarely paralytic,
during polio free first serotype to disappear
• Type 3- Paralysis less frequent
Less epidemic potential, scattered cases

8. Reservoir of infection :
• Man is the only known reservoir of infection.
• Most infections are subclinical.
• Mild and subclinical infections play a
dominant role in the spread.
• There are no chronic carriers.
• No animal source has yet been demonstrated.

9. Infectious material :
• virus is found in the faeces and oro-pharyngeal
secretions of an infected person.
Period of communicability :
• The cases are most infectious 7 to 10 days
before and after onset of symptoms.
• virus is excreted for 2 to 3 weeks in the faeces,
sometimes as long as 3 to 4 months.

10. Host factors
AGE :
• occurs in all age groups,
• but children are more susceptible than adults.
• In India polio is essentially a disease of infancy
and childhood.
• The most vulnerable age is between 6 months
and 3 years
SEX :
• Sex differences 3 males to 1 female.

11. RISK FACTORS :
• Several provocative or risk factors have been
found.
• They include fatigue, trauma, IM injections
• operative procedures such as tonsillectomy
undertaken especially during epidemics of
polio
• administration of immunizing agents
particularly alum-containing DPT.

12. IMMUNITY :
• maternal antibodies - first 6 months of life.
• Immunity following infection is fairly solid
• infection with one type does not protect
completely against the other two types
• Type-2 virus appears to be the most effective
antigen.

13. Environmental factors
• more likely during the rainy season.
• In India during June to September.
• Environmental sources : contaminated water,
food and flies.
• virus survives for a long time in a cold
environment.
• Overcrowding and poor sanitation provide
opportunities for exposure to infection.

14. Mode of transmission
FAECAL—ORAL ROUTE :
• main route of spread.
• directly through contaminated fingers where
hygiene is poor
• indirectly through contaminated water, milk,
foods, flies and articles of daily use.
DROPLET INFECTION :
• Close personal contact with an infected person
facilitates droplet spread.

15. Incubation period
• Usually 7 to 14 days
• (range 3 to 35 days).

16. Clinical spectrum
one of the following responses may occur.
1. Inapparent (Subclinical) Infection
2. Abortive Polio Or Minor Illness
3. Non-paralytic Polio
4. Paralytic Polio

17. Clinical Outcome of Poliovirus Infections
Paralytic poliomyelitis
Abortive-Clinical illness, no paralysis
Asymptomatic infection
90-95%4-8%
0.1-1%

18. INAPPARENT (SUB-CLINICAL) INFECTION :
• in 91-96 % of infections .
• no presenting symptoms.
• Recognition only by virus isolation or rising
antibody titres.

19. ABORTIVE POLIO OR MINOR ILLNESS :
• 4 to 8 % of the infections.
• only a mild or self limiting illness due to
viraemia.
• The patient recovers quickly.
• The diagnosis cannot be made clinically.

20. NON-PARALYTIC POLIO :
• 1 % of all infections.
• The presenting features are stiffness and pain
in the neck and back.
• The disease lasts 2 to 10 days.
• Recovery is rapid.
• The disease is synonymous with aseptic
meningitis.

21. PARALYTIC POLIO :
• less than 1 % of
infections.
• virus invades CNS
and causes varying
degrees of
paralysis.

26. Prevention
Primary Secondary Tertiary
A--Care of exposed
person
B—Immunization
C- Polio eradication
Strategies
-Symptomatic -Rehabilitation

27. Primary Prevention
• Health Education
• Improving Sanitation & Hygiene
• Vaccination

28. Vaccination
Immunization is the only effective in preventing
poliomyelitis.
• essential to immunize all infants by 6 months
of age to protect them against polio.
Two types of vaccines:
1. Inactivated (Salk) polio vaccine (IPV).
2. Oral (Sabin) polio vaccine (OPV).
• Both are safe and effective when used correctly.

29. Inactivated polio vaccine (IPV) (Salk)
• usually made from selected WPV (wild) strains
• administered by IM (preferred) or SC injection.
• refrigerated to ensure no loss of potency.
• Freezing avoided
• Available as a stand-alone or in combination.

30. initial course consists of 4 inoculations.
• 1st dose - given to infant @ 6 weeks old.
• The 1st 3 doses - @ intervals of 1-2 months
• 4th dose - 6-12 months after the 3rd dose.

31. Oral polio vaccine (OPV) (Sabin)
contains live attenuated virus (types 1,2 and 3).
• given as trivalent (tOPV) vaccine.
primary course of 3 doses @ 1 month intervals,
• zero dose to all children delivered in the hospital.
• 1st dose @ 6 weeks.
• complete vaccination before 6 months of age.
Bcoz most polio cases occur between 6 months
and 3 years.
One booster dose recommended 12 to 18 months
later.

32. • Dose = 2 drops or as stated on the
label.
• Vaccine be stored at -20 °C in a
deep freeze until used.
• hot water, hot milk or hot fluids
should be withheld for about half
an hour after the adm. of the
vaccine.
• However, Breast milk can be given
whenever the child is hungry.

34. Vaccine Derived Polio-virus (VDPV)
• OPV is a safe vaccine
• on rare occasions adverse events
• OPV adverse events may occur Vaccine-
associated paralytic poliomyelitis (VAPP)
• occurs in both OPV recipients and their
unimmunized child contacts.
• most frequently associated with type 3 (sabin)
(60% of cases); followed by type 2 and type 1

36. Indian Scenario
• In India vaccination against polio started in
1978. it was successful in covering around
40%.
• Universal immunization programme (UIP) was
launched 1995
• Pulse polio immunization programme along
with UIP

37. Strategies for polio eradication in India
• PPI days every year until poliomyelitis is
eradicated.
• Sustain high levels of routine immunization
coverage.
• Monitor OPV coverage at district level and
below.
• Improve surveillance - detecting all cases of AFP
due to polio and non-polio reason.
• Rapid case investigation, including the
collection of stool samples for virus isolation

38. • follow-up of all cases of AFP at 60 days to
check for residual paralysis.
• outbreak control for cases confirmed or
suspected to stop transmission.
• Even a single case is treated as an outbreak.
• preventive measures initiated within 48 hr of
notification of the case.
• complete and timely reporting of cases is
important element for the eradication.
• Reporting of all cases of AFP in children under
15 years of age is mandatory.

39. Mopping Up
• Mopping up activities are usually the last
stage in polio eradication.
"mopping up" involves
• door to door immunization in high-risk
districts, where wild polio virus is known or
suspected to be still circulating.
• This strategy is being implemented in India.

40. Pulse Polio Immunization
GOI conducted -
• the first round of PPI consisting of two
immunization days on…
• 9th December 1995 and 20th January 1996.
• The 1st PPI targeted all children under 3 years
irrespective of their immunization status.
• Later on, as recommended by WHO, the age
group increased from under 3 to under 5
years.

41. Mass Immunization campaign
(Pulse Polio Immunization)
Pulse meaning -
• Sudden, Simultaneous, mass administration of
OPV…
• on a single day- to all children 0-5 years of age
• …irrespective of their previous polio
vaccination status
• It is additional to routine immunization
• Also known as NIDs (National Immunization
Days)

42. • Two rounds 4 -6 wk apart during low
transmission season of polio (between
November to February)
• In India, the peak transmission is from June to
September.
• The dose of OPV during PPIs are EXTRA doses
• they DO NOT replace the doses during routine
immunization.

43. Several strategies utilized:
• Development of monovalent OPV. (mOPV1
and mOPV3)
• deployment of additional personel to assist
• social mobilization to reaching population
groups missed previous
• mobile teams to vaccinate children at transit
points (railway and bus stations)
• increased engagement and accountability of
political leaders and of health staff at all
levels.

44. Indian Scenario

45. last case of polio in the country
• was reported from Howrah of West Bengal
dated 13th January 2011.
• Thereafter no polio case has been reported in
the country.
• On 27th March 2014, India was declared as
non-endemic country for polio.

46. Gujarat- Last Case in 2007
Source-polio_frequently_asked_statistics_02_apr2015

47. Do Boond Zindagi ki ……….
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