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Poliomyelitis

The words polio (grey) and myelon (marrow, indicating the spinal cord) are derived from the Greek. It is the effect of poliomyelitis virus on the spinal cord that leads to the classic manifestation of paralysis. Poliomyelitis or poliio is a crippling and potentially deadly infectious disease caused by poliovirus that spreads from person to person invading the brain and spinal cord resulting into paralysis. Humans are the only known reservoir of poliovirus, which is transmitted most frequently by persons having infection.

 Due to unavailability of any cure till date vaccination is the best way of protection and the only way to control the spread of disease.

Generally ,two basic patterns of polio infection are :

  • Minor illness which does not involve the central nervous system (CNS), sometimes called abortive poliomyelitis,
  • A major illness involving the CNS, which may be paralytic or nonparalytic

Poliomyelitis generally spreads via the fecal-oral route by ingesting contaminated food or water and the oral-oral  route. In endemic areas, polioviruses can affect the entire human population. The disease has a seasonal transmission in temperate climates, with a peak occurrence during summer and autumn. 

References : www.cdc.gov
www.who.int
www.nlm.nih.gov
www.nhs.uk
www.ninds.nih.gov

  • Up to 95% of all polio infections are asymptomatic. Infected persons without symptoms shed virus in the stool and are able to transmit virus to other.
  • Approximately 4%–8% of polio infections result into a minor illness without clinical or laboratory evidence of central nervous system invasion. This is known as abortive poliomyelitis, and is characterized by complete recovery in less than a week. Three symptoms observed with this form of poliovirus infection are upper respiratory tract infection (sore throat and fever) ,gastrointestinal disturbances (nausea, vomiting, abdominal pain, constipation or diarrhea) and influenza-like illness.
  • 1-2% of polio infections leads to Nonparalytic aseptic meningitis (symptoms of stiffness of the neck, back, and/or legs), usually following several days after the above mentioned symptoms similar to that of minor illness. Increased or abnormal sensations can also occur. Typically these symptoms will last from 2 to 10days, followed by complete recovery.
  • Fewer than 1% of all polio infections result in flaccid paralysis which is a clinical manifestation characterized by weakness or paralysis and reduced muscle tone  . Paralytic symptoms generally begin 1 to 10 days after minor illness symptoms and progress for 2 to 3 days. Generally, no further paralysis occurs after the temperature returns to normal. Some signs and symptoms can include a loss of superficial reflexes, initially increased deep tendon reflexes and severe muscle aches and spasms in the limbs or back. The illness progresses to flaccid paralysis with diminished deep tendon reflexes, reaches a plateau without change for days to weeks, and is usually asymmetrical. Strength then begins to return. Patients do not experience sensory losses or changes in cognition.
  • Many persons with paralytic poliomyelitis recover completely and in most cases muscle function returns to some degree. Weakness or paralysis still present 12 months after onset is usually permanent.

References :

www.nhs.uk
www.cdc.gov

Poliomyelitis is caused by infection with a virus called as poliovirus. It colonizes in the gastrointestinal tract specifically the pharynx and intestine. It is highly contagious and spreads through either fecal-oral route , ingestion of contaminated food and water  or oral-oral route.

References : 

www.cdc.gov
www.nhs.uk
www.nlm.nih.gov

  • Viral Isolation

Poliovirus may be recovered from the stool or pharynx of a person with poliomyelitis. Isolation of virus from the cerebrospinal fluid (CSF) is diagnostic, but is rarely accomplished. If poliovirus is isolated from a person with acute flaccid paralysis, it must be tested further, using oligonucleotide mapping (fingerprinting) or genomic sequencing, to determine if the virus is “wild type” (that is, the virus that causes polio disease) or vaccine type (virus that could derive from a vaccine strain).

  • Serology

Neutralizing antibodies appear early and may be at high levels by the time the patient is hospitalized; therefore, a four fold rise in antibody titer may not be demonstrated.

  •  Cerebrospinal Fluid

In polio virus infection, the CSF usually contains an increased number of white blood cells (10–200 cells/mm3, primarily lymphocytes) and a mildly elevated protein (40–50 mg/100 mL)

References: 

www.cdc.gov
www.nhs.uk

Because there is no cure for polio, supportive therapy is given to the patient. Supportive care usually consists of treating the symptoms until the patient recovers. It includes medication for polio symptoms, exercise and a balanced diet.

  • Paralytic polio can lead to temporary or permanent muscle paralysis, disability, and deformities of the hips, ankles and feet. Although many  deformities can be corrected with surgery and physical therapy, these treatments may not be options in developing nations where polio is still endemic. As a result, children who survive polio may spend their lives with severe disabilities.
  • Aspiration pneumonia
  • Cor Pulmonale
  • Lack of movement
  • Lung Problems
  • Pulmonary edema
  • Shock
  • Permanent muscle paralysis
  • Urinary tract infection

References : 

www.cdc.gov
www.nlm.nih.gov

Due to unavailability of any cure till date vaccination is the best way of protection and the only way to control the spread of disease.

There are two types of vaccine that protect against polio: Inactivated polio vaccine (IPV) and oral polio vaccine (OPV). IPV, is given as an injection in the leg or arm, depending on patient's age. Polio vaccine may be given at the same time as other vaccines. Most people should get polio vaccine when they are children. Children get 4 doses of IPV, at these ages: 2 months, 4 months, 6-18 months, and booster dose at 4-6 years.

OPV consists of a mixture of live, attenuated (weakened) poliovirus strains of all three poliovirus types. Under the pulse polio immunization programme, all children below the age of 5 years are administered two doses of the oral polio vaccine per year. The oral polio vaccine is administered in the program, since it not only protects the child, but also gets disseminated to the community, thus resulting in widespread protection.

References : 

www.nhs.uk
www.cdc.gov 
www.vaccineindia.org
 

  • CREATED / VALIDATED BY : NHP CC DC
  • LAST UPDATED ON : Sep 16, 2015

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