Poliomyelitis, better known as polio, is a very contagious viral disease that causes mild symptoms in most patients who contract it (similar to any childhood disease), but on occasion can lead to permanent paralysis and death.

Polio was common until the 1950s until the Salk injectable vaccine was developed, which uses a non-infectious form of the virus to allow the body to develop immunity. At present, the Sabin vaccine, which uses a live but mild form of the virus is used because it can be administered orally. The vaccine can even be administered to infants with no risk of adverse effects. The vaccination is also very cheap, which allows it to be widely available even in the developing world. As a result, polio is very rare and most people in the developed world born after 1960 have probably never seen an active case.

One of the most famous victims of the disease was Franklin Delano Roosevelt, who developed the disease late in life and became crippled as a result. For the most part, the younger one is when one contracts polio, the less likely they are to suffer the severe symptoms. However, even very young children can die from the disease.

When polio runs unabated, it starts to effect the nervous system, resulting in gradual paralysis starting at the lower extremities. If the disease reaches the diaphragm, the patient will be unable to breathe without the help of a respirator.

Polio is passed through the digestive tract into feces. Exposure to even a small amount of contaminated feces will result in development of the disease to those who are not vaccinated or have already had the disease.

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