- August 23, 2021
- Posted by: admin1
- Category: DPN Topics
Subject – Science and Tech
Context– The Health Ministry has decided to vaccinate returnees from Afghanistan with free polio vaccines as a preventive measure.
- Polio also called as Poliomyelitis. It is a viral disease that destroys the nerve cells present in the spinal cord, causing paralysis or muscle weakness to some parts of the body.
- It is a contagious disease affecting the nervous system and is caused by Picornaviridae – a poliovirus.
- The virus is transmitted by person-to-person through the following ways –
- 1) Through the faecal-oral route.
- 2) By contaminated water or food.
- This virus primarily grows and multiplies in the intestine, from where it can attack thenervous system and will cause polio and paralysis on an advanced level.
- There are three individual and immunologically distinct wild poliovirus strains:
- Wild Poliovirus type 1 (WPV1)
- Wild Poliovirus type 2 (WPV2)
- Wild Poliovirus type 3 (WPV3)
- Symptomatically, all three strains are identical, in that they cause irreversible paralysis or even death.
- However, there are genetic and virological differences, which make these three strains separate viruses which must each be eradicated individually.
- WPV2 and WPV3 have been eradicated globally but WPV1 remains in circulation in Afghanistan and Pakistan.
- WPV2 was eradicated in 1999.
- There is no cure, but it can be prevented through immunisation.
- Oral Polio Vaccine (OPV):It is given orally as a birth dose for institutional deliveries, then primary three doses at 6, 10 and 14 weeks and one booster dose at 16-24 months of age.
- Injectable Polio Vaccine (IPV):It is introduced as an additional dose along with the 3rd dose of DPT (Diphtheria, Pertussis and Tetanus) under the Universal Immunisation Programme (UIP).
- For a country to be declared polio-free, the wild transmission of all three kinds of Polioviruses has to be stopped.
- For eradication, cases of both wild and vaccine-derived polio infection have to be reduced to zero.
- Eradication of a disease refers to the complete and permanent worldwide reduction to zero new cases through deliberate efforts. If a disease has been eradicated, no further control measures are required.
- However, elimination of a disease refers to reduction to zero or a very low defined target rate of new cases in a defined geographical area. It requires continued measures to prevent re-establishment of disease transmission.
Polio in India:
- India received polio-free certification by the WHO in 2014, after three years of zero cases.
- The last case due to wild poliovirus in the country was detected on 13th January 2011.