Wild Poliovirus

In News

• Mozambique has confirmed the first wild poliovirus Type 1 case in 30 years.
  • In August 2020, Africa was declared free of indigenous wild polio after eliminating all forms of wild polio from the region.

 Wild Poliovirus

• About:
  • Polio is a highly infectious disease, caused by the virus which multiplies in the intestine, from where it can invade the nervous system and can cause paralysis.
  • Once that happens, the patient is crippled for life because there is no treatment for the affliction. Colloquially they are referred to as wild polio virus.
• Variants
  • There are three types of wild poliovirus:
    • Type 1: still exists but efforts are going on to eradicate it.
    • Type 2: eradicated.
    • Type 3: eradicated.
• Transmission
  • The virus is transmitted by person-to-person, mainly through the faecal-oral route or less frequently, by a common vehicle (contaminated water or food).
  • Because the virus lives in the faeces of an infected person, people infected with the disease can spread it to others when they do not wash their hands well after defecating.
• Endemism:
  • Currently, wild poliovirus is endemic in two countries: Pakistan and Afghanistan.
  • The detection of Type 1 outside the two countries where the disease is endemic demonstrates the continuous risk of international spread of the disease until every corner of the world is free of Type 1.
• Symptoms:
  • Minor ones:
    • Tiredness
    • Nausea
    • Headache
    • Nasal congestion
    • Sore throat, cough
    • Stiffness in the neck and back and pain in the arms and legs
  • Major one:
    • Polio infection causes permanent loss of muscle function (paralysis).
    • Polio may be fatal if the muscles used for breathing are paralysed or if there is an infection of the brain.
• Cure
  • Though there is no cure for the polio vaccine. However, it is preventable by a vaccine.

How a country is declared polio-free?

• There are three variants of the poliovirus, numbered 1 to 3. For a country to be declared polio-free, the wild transmission of all three kinds has to be stopped.
• For eradication, cases of both wild and vaccine-derived polio infection have to be reduced to zero.
• Subsequently, WHO removes the country from the list of countries with active wild poliovirus.