Polio (also called
poliomyelitis) is a contagious,
historically devastating disease that was virtually eliminated from the
Western hemisphere in the second half of the 20th century. Although
polio has been around since ancient times, its most extensive outbreak
occurred in the first half of the 1900s until the polio vaccine was introduced in 1955.
At the height of the polio epidemic in 1952, nearly 60,000 cases with
more than 3,000 deaths were reported in the United States alone.
However, with widespread vaccination,
wild-type polio, or polio occurring through natural infection, was eliminated from the United States by 1979 and the Western hemisphere by 1991
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Symptom
Most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms.
About 1 out of 4 people with poliovirus infection will have flu-like symptoms that may include
Most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms.
About 1 out of 4 people with poliovirus infection will have flu-like symptoms that may include—
- Sore throat
- Fever
- Tiredness
- Nausea
- Headache
- Stomach pain
These symptoms usually last 2 to 5 days then go away on their own.
A
smaller proportion of people with poliovirus infection will develop
other more serious symptoms that affect the brain and spinal cord:
- Paresthesia (feeling of pins and needles in the legs)
- Meningitis
(infection of the covering of the spinal cord and/or brain) occurs in
about 1 out of 25 people with poliovirus infection
- Paralysis
(can’t move parts of the body) or weakness in the arms, legs, or both,
occurs in about 1 out of 200 people with poliovirus infection
Paralysis
is the most severe symptom associated with polio because it can lead to
permanent disability and death. Between 2 and 10 out of 100 people who
have paralysis from poliovirus infection die because the virus affects
the muscles that help them breathe.
Even children who seem to
fully recover can develop new muscle pain, weakness, or paralysis as
adults, 15 to 40 years later. This is called post-polio syndrome.
Note
that "poliomyelitis" (or "polio" for short) is defined as the paralytic
disease. So only people with the paralytic infection are considered to
have the disease.
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Polio Transmission
Polio
is a highly contagious illness that can spread easily from person to
person. In fact, when a person is infected with polio, it is expected
that polio transmission among susceptible household contacts will occur
in nearly 100 percent of children and over 90 percent of adults. Polio
transmission most often occurs through contact with stool from an
infected person. Less commonly, transmission occurs through contact with
respiratory droplets or saliva.
When a person is infected with poliovirus,
the virus resides in the intestinal tract and mucus in the nose and
throat. Poliovirus transmission most often occurs through contact with
stool of this infected person (known as fecal-oral transmission). Less
frequently, polio transmission can occur through contact with infected
respiratory secretions or saliva (oral-oral transmission).
Fecal-Oral Polio Transmission
Polio transmission most often occurs through contact with stool
from an infected person. This spread of poliovirus can happen in one of
several ways, which include:
- Eating food or drinking liquids that are contaminated with poliovirus. Poliovirus is commonly found in sewage water.
- Touching surfaces or objects contaminated with poliovirus (for
example, when changing diapers), and then placing the contaminated hand
in the mouth.
- Sharing foods or eating utensils with someone infected with poliovirus.
Who is at risk?
Polio can strike at any age, but it mainly affects children under MORE>>
