I recently met an elderly man who had been severely crippled by polio when he was a child. Thankfully, the disease has been eradicated in most of the world nowadays although it is still endemic in Afghanistan, Pakistan and Nigeria. Charities are making efforts to put in place an effective vaccination programme in these countries.
Worryingly, 105 new cases of polio appeared in Somalia last year accounting for almost half the recorded cases worldwide in 2012; Somalia having been declared polio-free in 2007. There are now concerns that polio may once again spread across countries previously declared as 'clear' as asylum seekers and immigrants from affected areas continue to migrate to the West in significant numbers. The government is fearful that those living in polio-free countries may become complacent and not have their children vaccinated.
What is polio?
Polio (or poliomyelitis) is a viral infection. It is extremely contagious, potentially fatal and can cause paralysis and breathing difficulties. Around 95% of polio victims show no symptoms at all. Polio can be non-paralytic or paralytic. Most people affected by non-paralytic polio go on to recover fully however those with the paralytic form of the disease usually suffer permanent paralysis.
There are several forms of paralytic polio:
Spinal polio attacks the spinal cord, causing damage to the motor neurons responsible for movement of the limbs and compromising respiration.
This form of polio attacks the neurons responsible for the senses and for the functions of breathing and swallowing.
This is a combination of both spinal and bulbar polio.
The most common victims fall into several vulnerable groups; those with compromised immune systems due to existing disease, pregnant women and the very young. Anyone who is not vaccinated against polio could contract the disease. Obviously, travelling to areas where polio is widespread also presents a risk.
Polio virus is highly contagious and is species specific, affecting only humans. The virus is usually present in the faeces of an infected person therefore areas where sanitation is very poor or non-existent readily harbour the disease. Food and water become contaminated and the virus then takes hold spreading from person to person through direct contact.
In its severest form, polio causes paralysis and death. The majority of sufferers however exhibit no symptoms and when symptoms are present they vary depending upon the form of polio.
Non-paralytic polio causes mild to severe flu-like symptoms whose duration varies from several days to a few weeks. Paralytic polio often starts off like this but progresses to far more debilitating and frightening symptoms; loss of muscle function, spasms, severe muscular pain, stroke-like signs including loss of use of limbs on one side of the body only.
Tests for poliomyelitis virus are usually via throat swab, stool samples or lumbar puncture.
Once the virus has been contracted, there is no cure and the focus is instead on management of the symptoms and pain.
Prevention of polio is via a simple vaccine. There are two forms of vaccine in use the safest of which, IPV, is made using inactivated poliovirus which is very safe and cannot itself cause polio. The vaccine is administered in a series of injections from birth to between four and six years of age. The much cheaper alternative is OPV. This is created from a weak form of poliovirus and has on occasion reverted to a highly dangerous form of the virus which can cause paralysis.
There have been many famous polio sufferers who have recovered fully or partially; Franklyn D Roosevelt, Jack Nicklaus, Mia Farrow, Neil Young, Joni Mitchell and Roman Emperor Claudius to mention but a few.