Causes

Polio is caused by the poliovirus. You can get the virus from contact with:

• An infected person
• Infected saliva or feces
• Contaminated water or sewage

The virus enters the body through the mouth. It travels to the intestines. There it reproduces quickly. The virus then travels through the blood and lymph fluid. It attacks and destroys areas of the nervous system.

Interaction of Lymph, Blood Vessels, and Intestines

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Risk Factors

The following factors increase your chance of developing polio:

• Lack of vaccination or incomplete vaccination
• Travel to countries where polio is still common (areas of Africa and Asia)
• Preschool child with immune disorder, exposed to live polio virus through vaccination
• Young adult exposed to poliovirus through contact with someone recently vaccinated
• Elderly adult
• Pregnancy
• Strenuous exercise
• Recent tonsillectomy or dental procedure
• Immunodeficiency