• Polio has been traced back
almost 6,000 years; great strides have been made in preventing this disease.
Polio is an infectious disease caused by viruses, the symptoms may range from
non to paralyse and death.
• Not receiving the polio vaccine is the highest risk factor for getting
infected with poliovirus; the viruses are only spread human to human by direct
and indirect contact.
• Symptoms and signs of polio vary from no symptoms to limb deformities,
paralysis, and death.
• Diagnosis of polio is based on the patient's history, physical exam, and
ongoing symptoms; the virus may be isolated from the patient's tissues to
confirm the diagnosis.
• There is no cure for polio; treatment is mainly supportive and is aimed at
limiting or reducing the patient's symptoms.
• For most patients, the prognosis is good because there are few or no symptoms;
however, the prognosis declines rapidly as some patients develop more severe
symptoms such as limb deformity, paralysis, difficulty breathing, and/or
inability to swallow foods.
• It is possible to prevent polio by vaccination; it may be possible to
eradicate polio.
• What causes polio?
Polio is caused by small RNA viruses. They are members of the enterovirus group
of the Picornavirus family. There are three types of polio viruses; type I is
responsible for about 85% of all paralytic infections. These types are
antigenically distinct strains of viruses; infection or immunity to one type
does not protect against the other two types, however, if immunity is
established to one or all of the three strains, immunity is lifelong. The
problem that these viruses cause is the destruction of spinal cord cells.
What are risk factors for polio? How does polio spread?
Currently, the World Health Organization (WHO) have certified that the Americas,
Western Pacific, and Europe are polio free; other areas have a low incidence of
polio, but people in war zones where vaccinations have been interrupted are at a
risk getting polio (for example, Afghanistan, Pakistan and Syria). The greatest
risk factor for polio is not being vaccinated. People with immunodeficiency (for
example HIV, cancer patients), very young individuals, pregnant females,
caregivers for polio patients, travellers to areas where polio is endemic, and
lab personnel who work with live polioviruses are at increased risk for polio.
The poliovirus lives in the throat and in the intestines; polio is spread
through contact with the feces or by droplet spread in a sneeze or cough. It can
also be spread by an infected person who has contaminated food or fluids by
touching or tasting them.