Poliomyelitis, also known as polio or infantile paralysis, is an acute, viral, infectious disease spread from person to person, most commonly via the fecal-oral route, by ingesting contaminated food or water.
Factors that increase the risk of polio infection or affect the severity of the disease include immune deficiency, malnutrition, tonsillectomy, physical activity immediately following the onset of paralysis, skeletal muscle injury due toinjection of vaccines or therapeutic agents, and pregnancy.
While roughly 90% of polio infections cause no symptoms at all, if the virus enters the blood stream affected individuals can exhibit a range of symptoms.
In about 1% of cases, the virus enters the central nervous system, infecting and destroying motor neurons, leading to muscle weakness and acute flaccid paralysis. Different types of paralysis may occur, depending on the nerves involved. The most common form of Polio is Spinal polio, which is characterized by paralysis that most often involves the legs. Bulbar polio leads to weakness of muscles innervated by cranial nerves. Bulbospinal polio is a combination of bulbar and spinal paralysis.
Poliomyelitis was first recognized as a distinct condition by Jakob Heine in 1840. Its causative agent, poliovirus, was identified in 1908 by Karl Landsteiner. Although major polio epidemics were unknown before the late 19th century, polio was one of the most dreaded childhood diseases of the 20th century.
By the early 1900’s, the world saw a dramatic increase in polio cases found primarily in cities during the warmer summer months. With the increased number of both children and adults left paralyzed, the development of a vaccine was strongly encouraged.
An Iron lung ward full of polio patients. An Iron lung was a form of medical ventilator that enabled a person to breathe when normal muscle control had been lost or the work of breathing exceeded the person's ability. Photo courtesy of scienceclarified.com
The polio vaccines developed in the 1950s have since reduced the global number of polio cases per year. Two effective vaccines have protected hundreds of millions of children against the disease: oral polio vaccine (OPV) and inactivated polio vaccine (IPV). However, in some cases the oral vaccine can lead to the individual developing polio.
Many organisations, such as WHO and UNICEF, have led polio vaccination programmes which have already made major inroads (and continue to do so) in reducing the number of those exposed to Polio. The other major threat to the success of this immunization programme is security. 23 clinic workers were shot dead in Pakistan and Nigeria between December and January by terrorists who believed the vaccination programme was part of an American plot. It was falsely believed by some of the attackers that the polio vaccination causes infertility. (1) (2)
To further complicate matters for these programmes, parents and officials are going to great lengths to immunise children after militants imposed a ban on polio vaccinations in Pakistan’s North Waziristan Agency. Government officials are withholding money and identity documents from groups affiliated with the ban, and parents are travelling long distances to get their children vaccinated, in some cases smuggling the vaccine back home. One father travelled 100km on a bus to get his son and niece vaccinated. Militants in the area banned all polio vaccinations in June 2012, to protest against the killing of civilians by drones. (3)
A child is vaccinated against polio in flood-affected Sain Dad Katohar village, Sindh province, Pakistan. Photo courtesy of guardian.co.uk
There is no cure for polio. The focus of modern treatment has been on providing relief of symptoms, speeding up recovery and preventing complications. Supportive measures include antibiotics to prevent infections in weakened muscles, analgesics for pain, moderate exercise and a nutritious diet. Treatment of polio often requires long-term rehabilitation including different types of therapy, braces, corrective shoes and surgery.
How LIFESAVER can help
The poliovirus is about 20-25 nanometres in size. LIFESAVER technology is able to filter out the poliovirus from contaminated water sources and cause a break in the virus’s transmission route (fecal-oral) enabling children to have a better start in life. LIFESAVER technology can also enable pregnant women to avoid contracting the virus as they are at particular risk as are people with immunodeficiency.
Polio on a global scale
While now rare in the Western world, polio is still endemic to South Asia and Africa, particularly Pakistan, and Nigeria respectively. A global effort to eradicate polio began in 1988, led by the WHO, UNICEF and The Rotary Foundation. These efforts have reduced the number of annual diagnosed cases by 99%; from an estimated 350,000 cases in 1988 to a low of 483 cases in 2001.
In 2012 cases decreased to 223. As of 2012, polio remains endemic in only three countries: Nigeria, Pakistan and Afghanistan. Since January 2011, there were no reported cases of the disease in India, and so in February 2012, the country was taken off the WHO list of polio endemic countries. It is reported that if there are no cases of polio in the country for two more years, it will be declared as a polio-free country.
Photo courtesy of polioeradication.org
Future for Polio
On 11 April 2013, hundreds of scientists and technical experts from 80 countries launched the Scientific Declaration on Polio Eradication. Currently, the world is very close to eradicating Polio, so scientists have joined voices to stress the achievability of polio eradication and endorse the Eradication and Endgame Strategic Plan, a new strategy by the Global Polio Eradication Initiative (GPEI) to reach and sustain eradication. (4)
Information courtesy of wikipedia, Guardian development news, Polioeradication.org and the BBC.
(1) 2013. ‘Nigeria polio vaccinators shot dead in Kano’. BBC News, [online] 8 April. Available at: <http://www.bbc.co.uk/news/world-africa-21381773> [Accessed 13 April 2013].
(2) 2013. ‘Pakistan 'policeman killed' guarding anti-polio worker’. BBC News [online] 26 February. Available at: http://www.bbc.co.uk/news/world-asia-21585291 [Accessed 13 April 2013].
(3) IRIN, part of the Guardian development network, 2013. ‘Battling Pakistan militants' ban on polio vaccines in North Waziristan'. Guardian online, [online] 2 April. Available at: <http://www.guardian.co.uk/global-development/2013/apr/02/pakistan-militants-polio-north-waziristan?INTCMP=SRCH>
[Accessed 13 April 2013].
(4) Piot, Peter, 2013. Poverty Matters Blog ‘With vaccination, communities on board and funds we can beat polio’. Guardian online, [online] 12 April. Available at: http://www.guardian.co.uk/global-development/poverty-matters/2013/apr/12/vaccination-communities-board-funds-polio [Accessed 13 April 2013].