Poliomyelitis

Poliomyelitis


Clinical manifestation:

  • Few suffer from minor illness, very few suffer from meningitis and less than 1% suffer from major paralytic disease

1. Asymptomatic illness:

  • In most of the infection is asymptomatic and self-limiting
  • 99% cases

2. Abortive poliomyelitis:

  • Non-specific symptoms such as headache, fever, sore throat, loss of appetite
  • Disease last for 5 days

3. Non paralytic poliomyelitis

  • Very few patients suffer from non-paralytic poliomyelitis
  • Stiffness of neck
  • Pain in back and neck
  • Disease last for 2-10 days

4. Paralytic Poliomyelitis:

  • Less than 1% patients suffer from major paralytic poliomyelitis
  • Paralysis in polio is asymmetric, descending, non-progressive and LMN type.
  • It damages the motor nerves causing oedema and muscle paralysis
  • Malaise
  • Anorexia
  • Nausea and vomiting
  • Sore throat
  • Constipation
  • Abdominal pain
  • Headache and fever
  • Flaccid paralysis: motor neuron damage
  •  Lower motor neuron lesion of the anterior horn cells of the spinal cord and affects the muscles of the legs, arms and/ or trunk
  • Bulbar paralysisrespiratory paralysis

5. Post-poliomyelitis muscle atrophy:

  • Muscle wasting
  • Loss of neuromuscular function
  • Physically Disabled

6. Death is rare. And if occur it is due to respiratory paralysi 

Lab diagnosis:

  • Specimen: nasal secretion, faecal samples, throat swab, CSF
  1. Electron Microscopy: virus detection
  2. Virus isolation from stool: 
  • Culture on monkey kidney cell line, Human amnion, HeLa, Hep-2, Buffalo green monkey (BGM), MRC-5 cell line
  1. Antibody detection: ELISA, complement fixation test
  2. Antigen detection: neutralization test
  3. Molecular diagnosis: PCR 

Treatment: no antiviral drugs

Prevention and control:

1. Vaccination

i. Inactivated Polio Vaccine (Salk type – killed):

  • Prepared by Jonas Salk in 1956
  • Also known as Inactivated poliovirus vaccine (IPV)
  • Prepared by formalin inactivation of poliovirus
  • It is injected deep subcutaneous or intramuscular
  • Given to child at age of 2 months, 4 months, at school entry age
  • Effective against all serotype of poliovirus
  • Produces circulatory antibody
  • Does NOT require stringent refrigeration
  • NOT effective in an epidemic

ii. Oral Polio Vaccine (Sabin type – live):

  • Developed by Albert Sabin in 1962
  • Contains live attenuated strain of all serotypes of poliovirus

The vaccine contains :-

  1. Over 300,000 TCID 50 of type 1 poliovirus
  2. Over 100,000 TCID 50 of type 2 poliovirus
  3. Over 300,000 TCID 50 of type 3 poliovirus 
  • Dose 2 drop (0.1 ml)
  • Schedule in National Immunization Programme of India.( 5 doses)

Dose and  Age

  1. OPV-0 (Zero dose)- At birth
  2. OPV-1 -6 weeks
  3. OPV-2  -10 weeks
  4. OPV-3  – 14 weeks
  5. OPV-B (Booster dose)  – 16-24 months
  • On administration, the virus multiplies in the intestine 
  • Induces intestinal and systemic immunity 
  • Intestinal immunity prevents infection of intestine by Poliovirus
  • Vaccine virus is excreted in the feces and can infect the unimmunized and induce immunity
  • Thus widespread herd immunity results, even if only approximately 66% of the community is immunized (100% coverage is not required).
  • It is administered Orally at 2 months of age simultaneously with first DPT
  • It is recommended for all children below 5 years
  • In endemic countries monovalent oral poliovirus type I vaccine (MOPvI) is introduced to eliminate the last reservoir of poliovirus
  • Colostrum produced in the first three days after child-birth contains secretory IgA antibody which might interfere with the production of immune response to OPV
  • Nevertheless, several studies show that among breastfed infants who are fed OPV in the first three days of life, 20-40 percent develop serum antibodies and 30-60 percent excrete vaccine virus.
  • Molar concentration of certain salts MgC12, Na2So4 protect polio virus from heat inactivation  
  • As it prevents heat inactivation mgCl2 can be added to polio vaccine so that it can be stored at a higher temperature. 

Complications of OPV

  • Being living viruses, the vaccine viruses, particularly typedo mutate 
  • In the course of their multiplication in vaccinated children, and rare cases of vaccine associated paralytic polio have occured in – 
  1. Recipients of the vaccine
  2. Thier contacts 

Contraindiations of OPV

  • Immunocompromized individuals
  • Patients suffering from leukaemias & malignancy or AIDS.
  • Persons receiving corticosteroids.
  • In pregnancy. 

2. Proper sanitation

3. Safe drinking water 

Vaccine derived polio virus (VDPV) 

Types of VDPV: 

  • c-VDPV: Person-to-person transmission in community
  • i-VDPV: Isolates from immunodeficient persons
  • a-VDPV: Ambiguous from health person or sewage isolates
IM injections and increased muscular activity lead to increased paralysis 

Diagnosis: 

  • VDPV is diagnosed by Real-time Reverse transcription-PCR nucleic acid amplification 

Key risk factors for cVDPV emergence 

Development of immunity gaps (due to low OPV coverage)

Low routine immunization coverage with trivalent OPV

Prior elimination of WPV types  Insensitive AFP surveillance
Exam Question
 

Clinical manifestation:

  • Few suffer from minor illness, very few suffer from meningitis and less than 1% suffer from major paralytic disease

1. Asymptomatic illness:

  • In most of the infection is asymptomatic and self-limiting
  • 99% cases

2. Abortive poliomyelitis:

3. Non paralytic poliomyelitis

4. Paralytic Poliomyelitis:

  • Less than 1% patients suffer from major paralytic poliomyelitis
  • Paralysis in polio is asymmetric, descending, non-progressive and LMN type.
  • Flaccid paralysis: motor neuron damage
  •  Lower motor neuron lesion of the anterior horn cells of the spinal cord and affects the muscles of the legs, arms and/ or trunk
  • Bulbar paralysis: respiratory paralysis

5. Post-poliomyelitis muscle atrophy

6. Death is rare. And if occur it is due to respiratory paralysis 

Lab diagnosis:

  • Specimen: nasal secretion, faecal samples, throat swab, CSF
  1. Electron Microscopy: virus detection
  2. Virus isolation from stool

Prevention and control:

1. Vaccination

i. Inactivated Polio Vaccine (Salk type – killed):

  • Effective against all serotype of poliovirus
  • Produces circulatory antibody
  • Does NOT require stringent refrigeration
  • NOT effective in an epidemic

ii. Oral Polio Vaccine (Sabin type – live):

  • Developed by Albert Sabin in 1962

 The vaccine contains :-

  1. Over 300,000 TCID 50 of type 1 poliovirus
  2. Over 100,000 TCID 50 of type 2 poliovirus
  3. Over 300,000 TCID 50 of type 3 poliovirus 
  • Dose 2 drop (0.1 ml)
  • Schedule in National Immunization Programme of India.( 5 doses)

Dose  Age

  1. OPV-0 (Zero dose)- At birth
  2. OPV-1 -6 weeks
  3. OPV-2  -10 weeks
  4. OPV-3  – 14 weeks
  5. OPV-B (Booster dose)  – 16-24 months
  • On administration, the virus multiplies in the intestine 
  • Induces intestinal and systemic immunity 
  • Intestinal immunity prevents infection of intestine by Poliovirus
  • Vaccine virus is excreted in the feces and can infect the unimmunized and induce immunity
  • Thus widespread herd immunity results, even if only approximately 66% of the community is immunized (100% coverage is not required).
  • In endemic countries monovalent oral poliovirus type I vaccine (MOPvI) is introduced to eliminate the last reservoir of poliovirus
  • Nevertheless, several studies show that among breastfed infants who are fed OPV in the first three days of life, 20-40 percent develop serum antibodies and 30-60 percent excrete vaccine virus.
  • Molar concentration of certain salts MgC12, Na2So4 protect polio virus from heat inactivation  
  •  As it prevents heat inactivation mgCl2 can be added to polio vaccine so that it can be stored at a higher temperature. 
  • Complications of OPV
  • In the course of their multiplication in vaccinated children, and rare cases of vaccine associated paralytic polio have occurred in – 
  1. Recipients of the vaccine
  2. Thier contacts
  •  Vaccine derived polio virus (VDPV) 

Types of VDPV: 

  • c-VDPV: Person-to-person transmission in community
  • i-VDPV: Isolates from immunodeficient persons
  • a-VDPV: Ambiguous from health person or sewage isolates

IM injections and increased muscular activity lead to increased paralysis

Don’t Forget to Solve all the previous Year Question asked on Poliomyelitis

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