Clinical Diagnosis (WHO case definition) “ A case of poliomyelitis is defined as any child under fifteen years of age with acute flaccid paralysis or any person with paralytic illness at any age when polio is suspected”
Poliovirus : three serotypes (P1, P2, P3) with different antigenicity
The virus can live in water for three months and in the faeces for six months.
The poliovirus is rapidly inactivated by heat, formaldehyde, chlorine and ultraviolet light.
Reservoir Cases : clinical & subclinical plays a role in the spread of infection Carriers: faecal temporary. There is no chronic carrier. Source of infection: Faeces and pharyngeal secretions of the infected person
Person Age and sex: In developing countries Poliomyelitis is a disease of young children and adolescents In developed countries adults were affected more commonly than children with increased both the disease severity and deaths. Sex difference have been noticed in the ratio of three male to one female
Time Poliovirus infection typically peaks in the summer months. Man is the only reservoir
Mode of transmission 1-Feaces (feco-oral): in areas with lack of personal hygiene especially in young children in developing countries. It results in infection not paralysis. 2-Droplet:in developed countries with high standard of sanitation, droplet is common mode of transmission during the acute phase of the disease when the virus is in the throat. 3-Direct contact with respiratory discharge 4- Common vehicle: ingestion of food or drink contaminated with faeces 5- Indirect contact with articles contaminated with pharyngeal discharge of infected person. Inlet The mouth and nose
Immunity in Polio Transplacentally acquired passive immunity After natural infection After immunisation Local immunity
Immunity to Poliovirus Infection Exposure to poliovirus initiates a complex process that eventually results in both humoral (systemic) and mucosal (local) immunity. Poliovirus infection provides lifelong immunity against the disease, but this protection is limited to the particular type of poliovirus involved (Type 1, 2, or 3) Thus, infection with one type does not protect an individual against infection of the other two types. IgMand IgG antibodies are detected in the serum as early as 1-3 days following natural infection but disappears after 2-3 months.
Poliomyelitis: Risk Factors Immune deficiency Pregnancy Poor sanitation and hygiene Poverty Unimmunized status, especially if <5 years Tonsillectomy: a risk factor for bulbar paralysis. Intramuscular injections or truama Genetics: No genetic susceptibility has been identified.
Abortive poliomyelitis 5% cases Influenza like symptoms 1-2 weeks later Lasts only for 2-3 days Clinical examination unremarkable Complete recovery
Non paralytic poliomyelitis 1% cases Initial minor illness-headache, nausea, vomiting, soreness and stiffness of neck muscles, fleeting paralysis of bladder and constipation Short symptom free interlude Major illness
Non paralytic poliomyelitis Nuchal and spinal rigidity are hallmark Tripod sign, Kiss the knee Neck rigidity, Kernigs sign Head drop Reflexes usually normal Changes in reflex indicate impending paralysis
Paralytic poliomyelitis-spinal 2nd phase of the illness Spotty paralysis Asymmetric flaccid paralysis One leg most common followed by one arm Absent DTRs
Paralytic poliomyelitis-spinal Absent DTRs No sensory deficits Full picture by 3 days. Usually no further progression Bowel and bladder dysfunction Older age and provocation paralysis the biphasic illness is not seen
Paralytic poliomyelitis-spinal Recovery is slow starting after several weeks of the disease, but usually within 6 months If not then residual paralysis Recovery may continue for as long as 18 months Atrophy, deformity and failure to grow
Paralytic poliomyelitis-Bulbar Nasal twang to voice and nasal regurgitation of food Inability to swallow and pooling of oral secretions Palatal and tongue involvement Vocal cord palsy
Paralytic poliomyelitis-Bulbar Vital centers in medulla being involved Ascending paralysis Autonomic disturbances Recovery is variable
Paralytic poliomyelitis-Encephalitis Involvement of higher centers Seizures,coma,spastic paralysis Peripheral & cranial nerve palsies Respiratory paralysis-due to variety of possibilities
Polymerase chain reaction amplification of poliovirus RNA from CSF or serologically, by comparing viral titers in acute and convalescent sera.
Diagnosis…cont Electrodiagnostic investigations reveal normal sensory nerve studies. Motor nerve studies: show normal to mildly slowed conduction velocities and low to normal amplitudes. MRI may be helpful to evaluate involvement of anterior horn of the spinal cord or other findings.
Outcome Complete recovery in abortive & non paralytic polio 60% mortality in bulbar polio & 5% in spinal polio Recovery beyond 6 months is unlikely
Four different oral polio vaccines are available to stop polio transmission. From left to right: mOPV3, mOPV1, bOPV and OPV
Oral polio vaccine Contains 3 serotypes of vaccine virus Grown on monkey kidney (Vero) cells Contains magnesium sulfate, phenolphthalein Heat sensitive – to be stored at –200 c Stored at 2-80 c during administration VVM on the vial
Oral polio vaccine Shed in stool for up to 6 weeks following vaccination – Herd immunity Seroconversion rates of 73%, 90% and 70% for 1, 2, 3 serotypes after 3 doses 4 doses in the first year of life and boosters-IAP recommendation Type 2 serotype disappears first with immunisation Used in pulse polio programme
Oral polio vaccine-Adverse reactions Vaccine associated paralytic poliomyelitis(VAPP)-250 to 800 cases annually-1/5 million doses Most common by type2 (type 3 as per Nelson and Park) Circulating vaccine derived polio viruses (cVDPV)-out breaks of paralytic polio
VACCINE VIAL MONITOR X 3 = bad:Don’t Utilize 1 = good:Utilize X 2 = good:Utilize 4 = bad:Don’t Utilize The central square is equal to, or darker than the surrounding circle The central square is lighter than the surrounding circle
Polio is suitable to be eradicated for the following reasons Polio only affects humans, there are no known animal reservoirs An effective, inexpensive vaccine is available: Oral Polio Vaccine (OPV) Immunity is life long There are no chronic carriers Half life of excreted virus in the sewage is 48hrs ( spread occurs only during this period)
AFP surveillance AFP is defined as sudden onset of weakness and floppiness in any part of body in a child <15 years or paralysis in a person of any age in whom polio is suspected Background rate of AFP 1/1,00,000 children is minimum
AFP surveillance Case notification and investigation –within 48 hours 2 stool samples 24 hours apart within 2 weeks (upto 60 days) Outbreak response immunization Active case searching Hot cases identification
AFP surveillance Collection of stool samples Transportation Eight national laboratories 60 day follow up
AFP surveillance – strategies High coverage of routine immunization Supplemental doses of OPV Surveillance of AFP cases Conducting mop-up vaccination campaigns
Before a WHO region can be certified polio-free, three conditions must be satisfied: There are at least three years of zero polio cases due to wild poliovirus; Disease surveillance efforts in countries meet international standards; and Each country must illustrate the capacity to detect, report and respond to “imported” polio cases
What is Post Polio Syndrome ? It is the late manifestation of acute paralytic polio. 25-40% of people who had paralytic polio15-40yr previously. They show symptoms of muscle and joint pain, general fatigue and weakness. Three indications of PPS: A. Previous diagnoses of polio B. Long interval following recovery: people usually live long but effect can occur during 30-35 years after the diagnoses. C. Gradual onset: weakness that tends to be perceptible until it interferes with daily activities.
Criteria For Diagnosis of Post Polio Syndrome A prior episode of paralytic poliomyelitis. EMG evidence of longstanding denervation. A period of neurologic recovery and functional stability preceding the onset of new problems (Usually >20 years).
Strategies of polio eradication There are four core strategies to stop transmission of the wild poliovirus A-Routine immunization of infants B-Supplementary immunization National immunization days ( EPI) Mopping up immunization ( EPI) C- Surveillance Acute flaccid paralysis and mop-up vaccination campaigns. D-An effective virological laboratory
REVERSE COLD CHAIN Sister kennys treatment Why PPI during nov-feb Brunhilde, lansing and lean WPV2 is not reported since 1999 Mc -1,VAPP-3