Polio, or "infantile paralysis", is an acute infectious disease caused by viruses that is acute and is characterized by a classic condition of sudden onset flaccid paralysis.

The motor deficit suddenly sets in, and evolution usually does not exceed three days. It usually affects the lower limbs asymmetrically and is characterized by muscle flaccidity (loss of muscle tone), preservation of sensitivity and absence of reflexes in the body part affected by the disease.


The mode of acquisition of poliovirus is oral, via fecal-oral transmission or rarely oral-oral. The initial multiplication of poliovirus occurs where it enters the body (throat and intestines). It then spreads to the bloodstream and then infects the nervous system, where its multiplication can lead to the destruction of cells (motor neurons), resulting in flaccid paralysis.

Poliovirus transmission occurs most often from the asymptomatic individual. Elimination is most intense 7 to 10 days before the onset of initial manifestations, but poliovirus may continue to be eliminated for 3 to 6 weeks. THE polio has no specific treatment.


Polio is still considered endemic by the World Health Organization in Nigeria, India, Afghanistan and Pakistan. There are prospects for eradication, but large numbers of people who move in and for endemic areas cause the risk of reintroduction of polio worrying and as long as there are endemic areas in the world, permanent. Not without reason, between 2003 and 2005, the disease was reintroduced, through imported cases, in 25 countries from which it had previously been eliminated.
In the Americas, the latest case of polio paralytic caused by wild poliovirus occurred in Peru in August 1991. In 1994 the elimination of the polio on the American continent, the first to obtain it, was attested by an International Commission. In Brazil, the last case of polio with the wild virus occurred in 1989, and the country received the Polio Elimination Certificate on December 12, 1994.

However, the risk of wild poliovirus reintroduction in countries where the disease has already been deleted, makes continued surveillance of cases of flaccid paralysis and the maintenance of immunization programs for polio. The vaccine against polio is part of Basic Vaccination Schedule, and is applied at 2, 4, 6, and 15 months of age. In addition, an annual National Immunization Campaign, in which children up to five years old are vaccinated.


A person who becomes infected with poliovirus may or may not develop the disease and 95% more infections are asymptomatic. The period between poliovirus infection and onset of symptoms (incubation) varies from 3 to 35 days. When they occur, the manifestations are similar to those of other diseases, such as respiratory infections (fever and sore throat, "flu") or gastrointestinal (nausea, vomiting, abdominal pain, constipation - "constipation" - or, rarely, diarrhea). Most of the time the manifestations disappear within a week and there is no central nervous system impairment.

In some people, after the initial manifestations, a picture of meningitis asepticusually with full recovery within ten days without occurring paralysis. However, one in every 200 infected people may develop paralytic polio. THE flaccid paralysis It usually begins 1 to 10 days after the initial manifestations and progresses for 2 to 3 days. THE polio has no specific treatment. Many people who develop paralytic polio they recover fully or partially, but 2 to 5% of children and 15 to 30% of adults may die.


THE polio can be prevented through vaccination and prevention measures against diseases transmitted by faecal contamination of water and food. There are two types of vaccines, the Sabin (oral, attenuated virus) and the Salk (injectable, virus inactivated). The oral polio vaccine should not be used in people with immunodeficiency (including people with HIV) and not in contactants situations in which the vaccine produced with virus inactivated (injectable).

The individuals with immunodeficiencyIn addition to the increased risk of vaccine polio, they can eliminate the virus in the feces for extended periods (months, years), which facilitates mutation ("reversal") and poses a risk to people. not vaccinated.