Poliomyelitis, better known as polio, is a serious viral infection. The polio virus attacks nerve cells in the body, destroys them, and causes paralysis.

Polio attacks begin with standard, flu-like symptoms, commonly; fever, headache, sore throat, and vomiting. These symptoms persist as stiffness of the neck and back develop, followed by weak muscles and movement difficulty. This leads to pain in the back and legs, particularly when these muscles are stretched and straightened. Finally, paralysis may develop causing the victim to lose the ability to stand or walk.

The most common type of polio is spinal poliomyelitis. It occurs when the polio viruses attack nerve cells that control the muscles of the legs, arms, trunk, diaphragm, abdomen, and pelvis. Bulbar paralysis is the most serious form of the disease, and is the result of damage to the nerve cells of the brain stem. Some of these nerves control muscles used in swallowing, eye movement, and movement of the tongue, face, neck, and possibly breathing and circulation of body fluids.

There are three viruses that cause polio, called type I, II and III. The viruses can grow only in living cells. They enter the body through the nose and mouth, and travel along nerve fibers or are carried by the blood to the central nervous system. Here, they enter nerve cells and multiply so rapidly that the cell is damaged or killed. Paralysis occurs when the cells are destroyed. Scientists are not clear on exactly how the virus spreads, or why polio epidemics occur, as was common in the past. It most probably spreads from the mouth, nose and intestines of infected people.

No drug has been found that can kill the polio virus or control it's spread in the body. A person's recovery period depends on immediate medical attention and good care. Complete rest in bed is considered one of the most important treatments due to the fact that bodily fatigue can make the disease more severe. Hot, moist bandages are used to relieve the pain in affected muscles. After the victim's fever goes down, physical therapists gently move the patients limbs to prevent deformities and painful muscle tightening. Later in the treatment process, more intensive exercises help to strengthen and retain muscles. Extensively paralyzed people can usually develop movement to carry on basic activities. Less severely affected patients usually [regain the] ability to do almost all of their previous activities. Some victims will need splints, braces, or crutches, and when breathing muscles are paralyzed, the use of a respirator for breathing. Two-thirds of these patients resume their normal breathing.

Luckily, two polio vaccines have been created. The first vaccine was developed by American researcher John Salk, and was given by injection. It was declared safe and effective in 1955. The second vaccine was also developed by an American researcher, named Albert Sabin. It was approved for use in the US in 1961 and is taken orally. It is recommended that children be vaccinated against polio early in life: at 2 months, 4 months, 18 months, and before beginning school.

Other polio facts include that it does not always result in sever illness. The mild symptoms can disappear after 24 hours, and the sickness may never be diagnosed as polio. There is also a somewhat mysterious condition called post-polio syndrome, where patients suffer new symptoms about 30 years after the original attack. These may include fatigue, muscle weakness, pain in the joints, and difficulty breathing. On the other hands, people who have the polio virus do not always develop the disease. It can be found in perfectly healthy people, especially during an epidemic. Polio is also called infantile paralysis because it often strike infants or children, and leads to paralysis.