Polio is abbreviation of
Poliomyelitis. It is also called infantile paralysis, actually it is a
transmittable viral illness that in its final stage causes paralysis, and
difficulty in breathing and even tends to death. It has existed since ancient
times. The disease was first predicted as an individual condition by Michael
Underwood in 1789 and the virus that causes polio was identified in 1908 by Karl
Landsteiner. United States is the first one where major outbreak started to
occur in the late 19th century regarding polio and in the 20th century it became
one of the most concerning childhood diseases in this area. The first polio
vaccine was developed in the 1950s.
In polio generally 90% to 95% of infections cause no symptoms and 5 to 10% of
people have minor symptoms such as: fever, headache, vomiting, diarrhea, neck
stiffness and pains in the arms and legs. These people are usually back to
normal within one or two weeks. In about 0.5% of cases there is muscle weakness
resulting in inability to move. This can occur over to a few days. Many but not
all people fully recover. In those with muscle weakness about 2% to 5% of
children and 15% to 30% of adults die. Years after recovery post-polio syndrome
may occurs with a slow development of muscle weakness similar to what the person
had during the initial infection. Poliovirus is usually spread from person to
person through infected feces entering the mouth. It may also be spread by food
or water containing human feces and less commonly from infected saliva. Those
who are infected may spread the disease even if no symptoms are present for up
to six weeks. The disease may be diagnosed by finding the virus in the feces or
detecting antibodies against it in the blood.
Beginning 23 February 1954, the vaccine was tested at Arsenal Elementary School
and the Watson Home for Children in Pittsburgh, Pennsylvania. Salk's vaccine was
then used in a test called the Francis Field Trial, led by Thomas Francis is the
largest medical experiment in history. The results of the field trial were
announced 12 April 1955 at the tenth anniversary of the death of President
Franklin D. Roosevelt whose paralysis was generally believed to have been caused
by polio). The Salk vaccine had been 60–70% effective against PV1 (poliovirus
type 1), over 90% effective against PV2 and PV3, and 94% effective against the
development of bulbar polio. Soon after Salk's vaccine was licensed in 1955
children's vaccination campaigns were launched.
The first dose of polio vaccine is given shortly after birth, usually between
1–2 months of age; a second dose is given at 4 months of age. The timing of the
third dose depends on the vaccine formulation but should be given between 6–18
months of age. A booster vaccination is given at 4 to 6 years of age, for a
total of four doses at or before school entry. In some countries, a fifth
vaccination is given during adolescence.
It is hoped that vaccination efforts and early detection of cases will result in
global eradication of the disease by 2018. In 2013; however, there were reports
of new cases in Syria and in May 2014, the World Health Organization declared a
public health emergency of international concern due to the outbreaks of disease
in Asia, Africa and the Middle East.