Polio (poliomyelitis) is a viral illness that damages nerves that control muscles, resulting in muscle weakness. In severe illnesses, a person can lose the ability to move both arms and legs (paralysis) and may be unable to breathe without help.

Symptoms of polio include:

• Headache.
• Sudden fever.
• Sore throat.
• Neck and back stiffness.
• Muscle weakness and pain.

Polio is now rare in developed countries, because most children receive immunization against the virus.