Poliomyelitis is a viral disease that can affect nerves and can lead to partial or full paralysis.
Polio; Infantile paralysis; Post-polio syndrome
Poliomyelitis is a disease caused by infection with the poliovirus. The virus spreads by:
Direct person-to-person contact
Contact with infected mucus or phlegm from the nose or mouth
Contact with infected feces
The virus enters through the mouth and nose, multiplies in the throat and intestinal tract, and then is absorbed and spread through the blood and lymph system. The time from being infected with the virus to developing symptoms of disease (incubation) ranges from 5 - 35 days (average 7 - 14 days). Most people do not develop symptoms.
Lack of immunization against polio
Travel to an area that has experienced a polio outbreak
Outbreaks can still occur in the developed world, usually in groups of people who have not been vaccinated. Polio often occurs after someone travels to a region where there has been an outbreak of disease. As a result of a massive, global vaccination campaign over the past 20 years, polio exists only in a few countries in Africa and Asia. These include Afghanistan, Cameroon, Equatorial Guinea, Ethiopia, Iraq, Israel, Nigeria, Pakistan, Somalia, and Syria.
There are three basic patterns of polio infection: subclinical infections, nonparalytic, and paralytic. Most people have subclinical infection, and may not have symptoms.
Post-polio syndrome is a complication that develops in some patients, usually 30 or more years after they are first infected. Muscles that were already weak may get weaker. Weakness may also develop in muscles that were not affected before.
When to Contact a Medical Professional
Call your health care provider if:
Someone close to you has developed poliomyelitis and you haven't been vaccinated
You develop symptoms of poliomyelitis
Your child's polio immunization (vaccine) is not up to date
Polio immunization (vaccine) effectively prevents poliomyelitis in most people (immunization is over 90% effective).
Modlin JF. Poliovirus. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 171.
Silver JK. Post-poliomyelitis syndrome. In: Frontera WR, Silver JK, Rizzo Jr TD, eds. Essentials of Physical Medicine and Rehabilitation. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2008:chap 137.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.