Polio, also known as poliomyelitis, is a very contagious disease caused by the poliovirus. Due to the introduction of a vaccine for polio in 1955, Canada has been free of polio since 1994.1, before this, the poliovirus infected tens of thousands of children in Canada,1 sometimes causing permanent damage to the nerve cells that control muscles, which lead to paralysis.1 It was referred to as “infantile paralysis” or “the crippler” for this reason.1
Because of the vaccine and a global effort to vaccinate, it is hoped that polio could be the second infection eradicated worldwide (the first one being smallpox).
While polio is most common in children under the age of 5, until polio has been completely eradicated worldwide, anyone who has not been immunized can be infected.2
The majority of people who are infected with the poliovirus will not experience any symptoms. Of the approximately 1 in 4 people who do develop symptoms, the following may occur:3,4
These symptoms generally resolve on their own in 2 to 5 days.4
While the majority of infections lead to either no symptoms or symptoms that resolve spontaneously within a few days, a small proportion of people who are infected with poliovirus develop more severe disease presentations.4 The virus can affect the brain and spinal cord (which are important for coordinating muscle movements) and this can result in:4
Between 2 and 10 out of 100 people who develop paralysis die because the nerves controlling the muscles involved with breathing are impacted.4
It is important to know that some individuals whose symptoms appear to resolve, may still develop new muscle issues, such as weakness or paralysis, later on in life as adults. This is referred to as ‘post-polio syndrome’.4
Polio is a highly contagious illness that is caused by the poliovirus.2 The poliovirus enters the body through a person’s mouth, mainly from food, water, or hands that are contaminated with the feces of an infected individual.2,4 Less commonly it can be spread through the respiratory droplets of an infected person. It then resides in the throat or digestive system, facilitating its spread to more people.4
The best way to prevent polio is through immunization with a vaccine.5, 6, 7,8, 9,10 Due to immunization, Canada has been polio free since 1994. However, polio has not been completely eradicated in all countries.2 Thus, there is still the risk that it could return to Canada (such as when an infected individual from another country comes to Canada), or could exist in countries that Canadian travellers go to.2,5 Therefore, it is important that Canadians continue to be vaccinated against polio8.
Polio is diagnosed after a positive test for the poliovirus is completed.11 It is important for individuals to consult their healthcare provider as soon as possible if they suspect that they have polio.
There is no cure for polio once contracted. If an individual tests positive for polio, their symptoms will be treated with options such as rest, fluids, physiotherapy, occupational therapy, or consultation with a neurologist, depending on the symptoms needing to be addressed.11