Polio viruses and polio immunisation ppt by Dr Prince C P

The causative agent of poliomyelitis (commonly known as polio), is a human Enterovirus and member of the family of Picornaviridae.
Poliovirus was first isolated in 1909 by Karl Landsteiner and Erwin Popper.
Poliovirus is one of the most well-characterized viruses, and has become a useful model system for understanding the biology of RNA viruses.
A breakthrough came in 1948 when the virus was successfully cultivated in human tissue in the laboratory by John Enders.
Enders, Weller and Robins, passaged the same strain in non neuronal cell culture.
Vaccines against poliomyelitis: the formalin-inactivated vaccine (IPV) by Jonas Salk(1953) and the live-attenuated vaccines (OPV) by Albert Sabin (1956)

1. Polio viruses DR.PRINCE C P Associate Professor , Department of Microbiology, Mother Theresa Post Graduate & Research Institute of Health Sciences (Government of Puducherry Institution)

2. Poliovirus The causative agent of poliomyelitis (commonly known as polio), is a human Enterovirus and member of the family of Picornaviridae . Poliovirus was first isolated in 1909 by Karl Landsteiner and Erwin Popper. Poliovirus is one of the most well-characterized viruses, and has become a useful model system for understanding the biology of RNA viruses.

3. Poliovirus Poliovirus is composed of an RNA genome and a protein capsid . The genome is a single stranded positive-sense RNA genome that is about 7500 nucleotides long. The viral particle is about 30 nm in diameter Icosahedral symmetry Non enveloped TYPES

4. Poliovirus

5. TYPES OF POLIO VIRUS The three serotypes of poliovirus, PV1, PV2, and PV3, each have a slightly different capsid protein. Capsid proteins define cellular receptor specificity and virus antigenicity . Type 1 (also known as Brunhilde ), As of November 2014, wild PV1 is highly localized to regions in Pakistan and Afghanistan. It is the type most ofte isolated from paralytic cases, most often the cause of epidemics Type 2(Lansing), Wild PV2 was declared eradicated in September 2014 after last being detected in October 1999 in Uttar Pradesh, India. Type 3 (Leon), As of November 2014, wild PV3 has not been seen since its 2012 detection in parts of Nigeria and Pakistan. They got their names from the cases in which they were first isolated.

6. TRANSMISSION The virus usually enters the environment in the faeces of someone who is infected. In areas with poor sanitation, the virus easily spreads from faeces into the water supply, or, by touch, into food. Individuals who carry the poliovirus can spread it via their faeces for weeks, even if they have shown no symptoms themselves. The time between infection and onset of paralysis (incubation period) is 10–21 days

7. pathogenesis Following poliovirus exposure, viral replication occurs in the oropharynx and the intestinal tract. Viremia follows, which may result in infection of central nervous system cells. The virus attaches and enters cells via a specific poliovirus receptor. Replication of poliovirus in motor neurons of the anterior horn and brain stem results in cell destruction and causes the typical clinical manifestations of poliomyelitis. Depending on the site of infection and paralysis, poliomyelitis can be classified as spinal, bulbar, or spino -bulbar disease. Progression to maximum paralysis is rapid (2–4 days); paralysis is usually associated with fever and muscle pain, and rarely progresses after the temperature has returned to normal. Between 2% and 10% of paralytic poliomyelitis cases are fatal. Infection with poliovirus results in lifelong, type-specific immunity.

8. pathogenesis

9. There are 3 possible outcomes ABORTIVE POLIOMYELITIS - A mild illness with influenza like symptoms that last for a few days or weeks. Symptoms include fever , fatigue ,headache , sore throat ,nausea, diarrhoea. Marked with full recovery. NON PARALYTIC POLIOMYELITI S-Most patients with CNS involvement develop non paralytic aseptic meningitis. Symptoms include that of the abortive polio with additional neurological symptoms like sensitivity to light and neck pain and stiffness. PARALYTIC POLIOMYELITI S-Occurs in 1% of the cases. It occurs when the virus (CNS) and replicates in motor neurons within the grey matter of spinal cord, brain stem resulting in the selective destruction of motor neurons leading to temporary or permanent paralysis. Symptoms include loss of muscle reflexes , loose or floppy limbs.

10. Laboratory Testing Laboratory studies, especially attempted poliovirus isolation, are critical for confirming whether a case of paralytic poliomyelitis is the result of wild or vaccine-related virus infection. Poliovirus is present in the stool in the highest concentration and for the longest time of any specimen, and therefore stool remains the most critical specimen for diagnosis. Because cell culture is extremely sensitive for the detection of poliovirus, it remains as sensitive, or more sensitive, than most molecular assays. A negative pan- enterovirus polymerase chain reaction (PCR) result cannot rule out poliovirus infection, and the use of cerebrospinal fluid (CSF) as a specimen for polio diagnostics is also an insensitive tool.

11. Importance of Rapid Identification Rapid investigation of suspected poliomyelitis cases is critical for identifying possible wild poliovirus transmission. Rapid detection of wild or virus-related cases permits the timely implementation of controls to limit the spread of imported wild poliovirus or cVDPVs and maintain the eradication of wild poliovirus. Moreover, rapid investigation of suspected cases will allow collection of specimens for poliovirus isolation, which is critical for confirming whether a case of paralytic poliomyelitis is the result of wild or vaccine-related virus infection.

12. WHY THERE IS A NEED OF VACCINE ? Polio (poliomyelitis) mainly affects children under 5 years of age. 1 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 74 reported cases in 2015. The reduction is the result of the global effort to eradicate the disease. As long as a single child remains infected, children in all countries are at risk of contracting polio. Failure to eradicate polio from these last remaining strongholds could result in as many as 200 000 new cases every year, within 10 years, all over the world.

13. DEVELOPMENT OF POLIOVIRUS VACCINES A breakthrough came in 1948 when the virus was successfully cultivated in human tissue in the laboratory by John Enders. Enders, Weller and Robins, passaged the same strain in non neuronal cell culture. Vaccines against poliomyelitis: the formalin-inactivated vaccine (IPV) by Jonas Salk(1953) and the live-attenuated vaccines (OPV) by Albert Sabin (1956) .

14. POLIO VIRUS VACCINE ORAL POLIO VACCINE(OPV)• Uses attenuated poliovirus INACTIVATED POLIO VACCINE (IPV)• Uses inactivated poliovirus

15. OPV vs IPV

16. MASS IMMUNIZATION PROGRAMMES AGAIST POLIO

17. PULSE POLIO PROGRAMME History In India, vaccination against polio started in 1978 with Expanded Program on Immunization (EPI). By 1984, it covered around 40% of infants, giving three doses of OPV to each. In 1985, the Universal Immunization Program (UIP) was launched to cover all the districts of the country. UIP became a part of child survival and safe motherhood program (CSSM) in 1992 and Reproductive and Child Health Program (RCH) in 1997. This program led to a significant increase in coverage, up to 95%. The number of reported cases of polio also declined from 28,757 during 1987 to 3,265 in 1995. In 1995, following the Global Polio Eradication Initiative of the World Health Organization (1988), India launched Pulse Polio immunization program with Universal Immunization Program which aimed at 100% coverage.

18. KEY OBJECTIVES The Pulse Polio Initiative (PPI) aims at covering every individual in the country. It aspires to reach even children in remote communities through an improved social mobilization plan. Not a single child should miss the immunization, leaving no chance of polio occurrence. Cases of acute flaccid paralysis (AFP) to be reported in time and stool specimens of them to be collected within 14 days. Outbreak response immunization (ORI) to be conducted as early as possible. Maintaining a high level of surveillance. Performance of good mop-up operations where polio has disappeared.

19. ELIMINATION OF POLIO IN INDIA The last reported cases of wild polio in India were in West Bengal and Gujarat on 13 January 2011. On 27 March 2014, the World Health Organization (WHO) declared India a polio free country, since no cases of wild polio had been reported in for three years. As of mid-2016, only Afghanistan, Nigeria and Pakistan have wild polio cases

20. INDRADHANUSH PROGRAMME LAUNCH DATE Mission Indradhanush is a health mission of the government of India. It was launched by Union Health Minister J. P. Nadda on 25 December 2014. Objective Aims to cover all those children by 2020 who are either unvaccinated, or are partially vaccinated against 7 vaccine preventable diseases The diseases are – diphtheria, whooping cough, tetanus, polio, tuberculosis , measles and hepatitis B

21. summary Poliomyelitis is an acute viral infection caused by polioviruses. It is a crippling disease. Causative organism: Three types of polioviruses (Type I, II, III) Incubation period: The usual range of incubation period is 7 to 21 days. Mode of Transmission: Faeco – oral route: Through contaminated water, food, fingers etc. Clinical manifestations: Paralysis Preventive measures: Immunization is the sole effective means of preventing, poliomyelitis. Both killed and 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 1. Inactivated (salt) polio vaccine (IPV) 2) Oral (Sabin) polio vaccine (OPV)

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