Polio (cont.)

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What causes polio?

The symptoms of polio are caused by the poliovirus, which is a small RNA virus that is spread through contact with the oral mucosa (mouth, nose, etc). Most commonly, the virus attaches to and infects intestinal cells, multiplies, and is excreted in the stool of the infected individual. Rarely, in 2% of the cases, the virus spreads from the gastrointestinal tract to the nervous system and causes paralytic disease.

How is polio spread?

Polio is spread in an "oral-fecal" manner. Person-to-person infection occurs by contact with infected mucus, phlegm, feces, or by contact with food and water contaminated by feces of another infected individual.

What are signs and symptoms of polio?

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The signs and symptoms of polio differ depending on the extent of the infection. Signs and symptoms can be divided into paralytic and non-paralytic polio.

In non-paralytic polio which accounts for most individuals infected with polio, patients remain asymptomatic or develop only mild flu-like symptoms, including fatigue, malaise, fever, headache, sore throat, and vomiting. The symptoms, if present, may only last 48-72 hours, though usually they last for one to two weeks.

Paralytic polio occurs in about 2% of people infected with the polio virus and is a much more serious disease. Symptoms occur as a result of nervous system and spinal cord infection and inflammation. Symptoms can include

  • abnormal sensation,
  • breathing difficulty,
  • difficulty swallowing,
  • urinary retention,
  • constipation,
  • drooling,
  • headache,
  • mood swings,
  • muscle pain and spasms, and
  • paralysis.

Approximately 5%-10% of patients who develop paralytic polio die from respiratory failure, since they are unable to breathe on their own. That is why it is imperative that patients receive appropriate medical evaluation and treatment. Prior to the vaccine era and the use of modern ventilators, patients would be placed in an "iron lung" (a negative pressure ventilator, which was used to support breathing in patients suffering from paralytic polio).

Medically Reviewed by a Doctor on 1/16/2014

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