Polio

Summary

• Polio is an illness caused by a virus of the family Picornaviridae.
• Although now very uncommon in the Western world, there continues to be a threat that it will get out of control
• The virus will most often cause a minor illness with symptoms similar to an upper respiratory tract infection, but it can cause an aseptic meningitis, and, more seriously, spinal cord inflammation resulting in paralysis.
• Polio leaves a significant number of people paralysed in one or more limbs.
• There is no specific treatment for polio, but it can effectively be prevented by vaccination.

Alternative names

Infantile paralysis, acute anterior poliomyelitis

What is polio?

Polio, strictly speaking called poliomyelitis, is a viral infection which has a wide range of signs and symptoms.

These can range from minor, flu-like illnesses, to weakness and paralysis of various muscle groups.

What causes polio?

Polio is caused by a virus belonging to the family Picornaviridae. There are three different types: 1, 2 and 3. Polio was an important disease in temperate Western countries (Europe and the USA) during the last part of the nineteenth century and well into the twentieth century, until a vaccine was developed in the 1950s. The disease is now very rarely seen (a consequence of importation) in these countries.

However, polio remains a serious public health threat in the developing world to this day. Despite a global vaccination campaign by the WHO, there are still pockets of the disease in a few countries in Asia and Africa where there is cultural or political resistance to vaccination, or where vaccination programmes have broken down due to war or other upheaval.

In South Africa, there is an ongoing intensive polio vaccination programme and no cases have been identified since the 1980's. However, polio outbreaks occurred in neighbouring Angola and Namibia in the early 1990's and again in Namibia in 2006.

Who gets polio and who is at risk of the disease?

Where there are poor socio-economic circumstances and poor sanitation and hygiene, the virus is potentially present year-round. If polio is endemic, people can acquire a natural immunity since they are exposed to it as children, often getting the mild form of the illness. In these circumstances, the paralytic form of polio is usually seen only in children less than five years old. In outbreaks in na

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