Polio – an infectious disease caused by a virus, which destroys the motor neurons in the gray matter of the spinal cord or the brain. This results in paralysis of the skeletal muscles.
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 to 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.
- Mood swings.
- Muscle pain and spasms.
Approximately 5% to 10% of patients who develop paralytic polio often 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).
Polio is caused by infection with the poliovirus
This virus is highly contagious, and is passed on through food and water contaminated with the stool (feces) of infected people. It can take 4 to 21 days before symptoms appear and an infected person can pass the virus on to other people even before symptoms appear.
Infection with polio happens when the virus enters the body through the mouth, multiplies in the throat and intestine, and spreads through the blood to the central nervous system. There, the virus attacks nerve cells, which can lead to paralysis.