Polio virus

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Slide 1: 

The poliovirus … Brunhilde Lansingh Leon

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Small, icosahedral (27-30nm dia) Non-enveloped particle Single stranded RNA as genome, ~7500 nt serves as messenger RNA in infected cells Capsid made of 4 proteins. VP1, VP2,VP3 and VP4 Three Antigenic types: Poliovirus type 1, Poliovirus type 2 and Poliovirus type 3 Family: Picornavirideae. Genus: Enterovirus Poliovirus

History : 

History Recognized in late 19th century 1st clinical description by Heine 1st description of epidemic by Medin in 1887 1953 US - 20 / 100000 Eradicated except for Asia & Africa continents

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The disease of poliomyelitis has a long history. The first example may even have been more than 3000 years ago. An Egyptian stele dating from the 18th Egyptian dynasty (1580 - 1350 BCE) shows a priest with a deformity of his leg characteristic of the flaccid paralysis typical of poliomyelitis. .

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In 1928, Philip Drinker and Louis Shaw at Harvard Medical School introduced the iron lung to help individuals suffering from acute poliomyelitis. Polio impaired patients' ability to breathe by paralyzing the diaphragm and intercostal muscles; the iron lung provided relief in the form of artificial respiration. It consisted of a sealed chamber in which air pressure is alternately reduced and increased. The patient was placed in the chamber with his/her head emerging from a port at one end. Each cycle of vacuum within the chamber allowed their lungs to be filled with atmospheric air; subsequent increase of pressure forced exhalation of air from the lungs.

Background : 

Background In May 1988, World Health Assembly decision The Partners are - WHO, UNICEF, Rotary, CDC, GoI Long term financial & humanitarian benefits Surveillance & Lab network

Clinical Outcome of Poliovirus Infections : 

Clinical Outcome of Poliovirus Infections Paralysis is unusual manifestation of infection Paralytic poliomyelitis Clinical illness, no paralysis Asymptomatic infection Spinal Bulbospinal Bulbar Encephalitic 85-90% 10-15% <1% Rare

Clinical Aspects of Polio : 

Clinical Aspects of Polio 90 - 95 % infection not apparent 4 - 8 % minor illness Abortive polio No Paralysis Recovery is rapid & complete Polio - 0.5 - 1 %

Clinical Aspects of Polio..2 : 

Clinical Aspects of Polio..2 Minor & Major phase (Biphasic fever) Minor : Similar to Abortive polio Major : Muscle pain, Spasms, return of fever & rapid onset of Flaccid paralysis Signs of meningeal Irritation are present during major viraemia

Clinical Aspects of Polio..3 : 

Clinical Aspects of Polio..3 Affected muscles are hypotonic DTR- diminished or absent Touch & pain normal Asymmetrical paralysis Legs > Arms Proximal muscle involvement Spinal, Bulbar & Spinobulbar forms

Polio Vaccines : 

Polio Vaccines Oral Polio Vaccine(OPV) Live Attenuated Vaccine Sabin 106 , 105, 105.8 TCID50 per dose Both systemic & local immunity Used for mass campaigns Useful during control of epidemic Cheap & easy to administer

Polio Vaccines..2 : 

Polio Vaccines..2 Inactivated Polio Vaccine(IPV) Killed Vaccine Salk Only Systemic immunity Not useful for mass campaigns Cannot be administered during epidemics Costly & Administration requires trained manpower

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Cameroun Nigeria WORLD - WILD POLIO VIRUS CASES - 2006 1998 CASES IN 17 COUNTRIES India Yemen Indonesia Niger Afghanistan Somalia Bangaladesh Pakistan Ethopia Nepal Democratic Republic of Congo Namibia Angola Kenya Cameroon Chad * data as on 11th April 2007

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Cameroun Nigeria WORLD - WILD POLIO VIRUS CASES – 2007 1172 CASES IN 12 COUNTRIES India Niger Somalia Pakistan Democratic Republic of Congo * data as of 16th Jan 2008 Afghanistan Myanmar Angola Chad Sudan Nepal

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Location of poliovirus by type, 2007* * data as on 18th January 2008 ** three cases (one in UP, two in Bihar) reported mixture of P1 wild and P3 wild

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Polio cases of type 1, India Year * data as on 18th January 2008

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Polio cases of type 3, India Year * data as on 18th January 2008

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Monthly incidence of wild polio cases 1998-2007* * data as on 22nd June 2007

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Wild Virus Cases 2000

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Wild Virus Cases 2001 Nandurbar

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Wild Virus Cases 2002

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Wild Virus Cases 2003

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Wild Virus Cases 2004

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MAHARASHTRA - 2006 INDMHBED06020 Onset : 18/07/2006 INDMHBMC06172 Onset : 12/08/2006 INDMH-BMC06208 Onset : 24/08/2006 INDMHTHN06530 Onset : 10/10/2006 INDUPBBK06199 Onset : 02/11/2006 Total Cases: 5 P1 Wild Case * data as on 25th December 2006

Surveillance – what is it? : 

Surveillance – what is it? Surveillance is data collection for action Data Timely Precise Core data Action Immediate Focused Appropriate

Why is surveillance needed? : 

Why is surveillance needed? To know where the disease is To know who are affected To know when the disease occurs To drive immunization activities To know when virus transmission is gone!

AFP- Case Definition : 

AFP- Case Definition Sudden onset weakness and floppiness in any part of the body in a child < 15 years of age or paralysis in a person of any age in which polio is suspected.

AFP Surveillance : 

AFP Surveillance Syndromic Approach Net cast wider Data used to direct immunization activities Helps in measuring progress Mandatory for certification

AFP Surveillance… Contd. : 

AFP Surveillance… Contd. The only prominent finding in Polio is Paralysis of one or more limbs Acute in Onset & Flaccid Type Polio cannot be diagnosed clinically All cases of Acute Onset Flaccid Paralysis(AFP) are reported & investigated

WHY AFP & Not only Polio : 

WHY AFP & Not only Polio Difficult to distinguish clinically from other causes of AFP Polio cases with atypical presentation may be missed Syndromic approach of investigation all AFP ensures detection of all Polio cases

AFP Surveillance…Contd. : 

AFP Surveillance…Contd. AFP cases classified as Polio & Non-Polio “Background Rate” is at least 2 Non-Polio cases / 1,00,000 children < 15 years / year Commonest Non-Polio conditions are Gullain-Barre Syndrome Transverse Myelitis Traumatic Neuritis

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Please Report Hypokalemic Paralysis Post diphtheritic paralysis Bell’s palsy Hemiplegia / Paresis < 5 years Transient Flaccid Paralysis


REPORTING SITE Any Hospital / Clinic where patients are treated Likely to see AFP case In MP; temples are also included A Nodal Officer is identified

Case Investigation : 

Case Investigation As early as possible Must be < 48 hrs. from report History to rule out – Paralysis since birth, Major Trauma Examination Complete information is recorded Complete address with landmarks

Stool Collection : 

Stool Collection 2 Stool specimens 24-48 hrs. apart Within 14 days of onset of paralysis Can be done upto 2 months from onset At least 8 gm. Each Special container must be used Side of the container to be labeled with Name & EPID No. Voided stool preferred “Reverse Cold Chain”to be maintained

Stool CollectionLess preferred method : 

Stool CollectionLess preferred method Using Rectal tube Rounded end with holes to be inserted without squeezing the walls of the tube Insert > 1/2 tube’s length Squeeze the walls slightly & withdraw the tube If no stool, insert once more only


INADEQUATE STOOLS Collection > 14 days Quantity < 8 gms. Leakage or dryness Break in reverse cold chain Documentation required to be send to Expert Committee, Delhi 60th Day FU must be timely Case classified as Discarded or Compatible


LABORATORY NETWORK 8 Laboratories 7 National laboratories 1 Global specialized Laboratory (EVRC Mumbai) Inter- typic differentiation ( P1,P2 or P3 ) in National Lab Intra-typic differentiation (ITD) Wild or Vaccine - Mumbai, Chennai & Lucknow lab only All laboratories are accredited by WHO

Outbreak Response Immunization (ORI) : 

Outbreak Response Immunization (ORI) For every AFP case After stool collection 1 round h-t-h children < 5 years age Limited activity (not more than 500 children ) All children in the village only 1 ward in the Urban areas

60th Day FU Examination : 

60th Day FU Examination Done on 60th day from onset Date of onset taken as Day 0 Must be done < 70 days from onset Type of paralysis is verified (Flaccid or Spastic) Presence or absence of Residual weakness

Classification of AFP cases : 

Classification of AFP cases Every AFP case is classified as Polio – If stool sample contains polio-virus Non-Polio or Discarded – If stool samples are –ve for virus & sample is collected < 14 days. Diagnosis is given like GBS,TM,TN etc. Compatible – If stool samples are inadequate & the case cannot be classified as Non-Polio case

Compatible Cases : 

Compatible Cases Cases with inadequate stools Stool samples -ve for Polio virus Could not be discarded as Non-Polio Indicates Surveillance failure

Cluster of Compatible Cases : 

Cluster of Compatible Cases 2 or more cases in a district or adjoining areas of 2 districts in a period of 2 months Cluster indicates the presence of Wild virus circulation Needs investigation

Slide 48: 

Thank You

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