Poliomyelitis (POH-lee-o-my-uh-LYE-tis), or polio, is a disorder caused by the poliovirus and involves damage of nerve cells. It may lead to weakness and deterioration of the muscles and sometimes paralysis. Thanks to an extremely successful vaccination * program, this disease has disappeared from the United States and much of the world, although it still exists in some countries.

What Is Poliomyelitis?

Poliovirus, part of the enterovirus * group, makes its home in the alimentary canal, which includes the mouth, esophagus, stomach, intestines, colon, and rectum; but when the viral infection spreads it can destroy nerve cells that make muscles work. These damaged nerve cells, called motor neurons, cannot rebuild themselves. As a result, the body's muscles no longer function correctly.

Types of paralytic polio include spinal, bulbar (BUL-bar), and bulbospinal (bul-boh-SPY-nul). The spinal type is most common, affecting the muscles of the legs, trunk, and neck. The bulbar form involves nerves of the brain stem * and can cause problems with breathing, talking, and swallowing. Bulbospinal polio is a combination of the first two types.

How Common Is Poliomyelitis?

Polio has been essentially wiped out in the United States and many other developed countries following the introduction of a polio vaccine in 1955. Before that, polio occurred in epidemic *


1955: Jonas Salk's vaccine containing dead, or inactive, poliovirus (IPV) is licensed, and large numbers of schoolchildren are vaccinated, leading to a marked decrease in the number of polio cases over the next few years and a 60 to 70 percent prevention rate.

1963: Albert Sabin's oral polio vaccine (OPV), containing a live but weakened virus, becomes the new recommended vaccination in the United States. It offers lifelong protection; can be swallowed; and is easy to administer. In very rare cases, however, it causes paralytic polio.

1979: The last cases of wild polio (polio that is not vaccine-related) are reported in the United States.

2000: IPV becomes the exclusive polio vaccine used in the United States. Experts believe that because polio has virtually disappeared in the United States, the benefits of using OPV are no longer worth the very small risk of contracting the disease from this form of the vaccine.

In its most severe form, polio causes paralysis of the muscles of the legs, arms, and respiratory system. All muscle tone is lost in the affected limb, and the muscle becomes weak and begins to wither, as shown in the illustration above.

In its most severe form, polio causes paralysis of the muscles of the legs, arms, and respiratory system. All muscle tone is lost in the affected limb, and the muscle becomes weak and begins to wither, as shown in the illustration above.
llustration by Electronic Illustrators Group. © 2016 Cengage Learning®.

Is Poliomyelitis Contagious?

Poliovirus is extremely contagious and can pass easily from person to person. The virus typically is found in feces and can spread when people touch contaminated objects and then touch the mouth or nose, or handle food without washing their hands first. The virus can live in feces for weeks, making the spread of infection difficult to control. It can also spread through contact with tiny drops of fluid from a sick person's mouth or nose, or by drinking contaminated water. After entering the mouth or nose, the virus multiplies in the throat or gastrointestinal tract and eventually invades the bloodstream, where it can move to other parts of the body. In a very small number of people, about 1 to 2 percent, the virus invades the central nervous system (the brain and spinal cord) where it can cause paralysis.

The infection is most contagious 7 to 10 days before symptoms begin and for the same period after they appear. The virus spreads more readily in areas with poor sanitation.

What Are the Signs and Symptoms of Poliomyelitis?

Polio in History

Polio has caused paralysis and death for most of human history. Reference to paralytic poliomyelitis can be found in Egyptian stone engravings more than 3,000 years old. At the start of the 20th century, few people had ever heard of the disease until epidemics of polio began to occur with regularity in developed countries. In the summer of 1916, polio became a more familiar condition in the United States when a devastating epidemic struck New York City, with over 9,000 cases and 2,343 deaths. The outbreak left 27,000 people paralyzed across the United States and 6,000 dead. Almost 40 years later, on April 12, 1955, the announcement came that Dr. Jonas Salk had developed the first effective vaccine against paralytic poliomyelitis. With the development of this and other later vaccines, polio was eradicated throughout most of the industrialized world.

How Is Poliomyelitis Diagnosed?

A doctor may suspect polio in a sick patient with paralysis, particularly if the person has not been immunized against polio. The doctor may follow up with questions about recent travel, because while the polio vaccine has wiped out the disease in the United States, polio still occurs in some other countries. During a physical examination, a doctor looks at the extent of the muscle paralysis and may take samples of blood, bowel movements, fluid from the throat, or cerebrospinal fluid * and have them tested for the virus.

What Is the Treatment for Poliomyelitis?

There was no cure for polio as of 2016. Doctors instead focus on easing a patient's symptoms, which includes controlling pain and muscle spasms, and matching supportive care to the patient's muscle weakness. For abortive cases and many nonparalytic cases of polio, a doctor typically recommends rest, fluids, and pain medication, as well as moist heat on muscles to ease stiffness. The doctor may also prescribe antibiotics to treat urinary tract and other bacterial infections that can occur in patients with polio.

Patients with severe cases of polio, particularly the paralytic form, often require hospitalization. In the 1940s and 1950s, medical professionals placed patients inside metal tanks called iron lungs, which assisted their breathing. Although medical technology has progressed since then, many people who have polio still need machines called ventilators * to help them breathe as they recover, as well as additional supportive care. Patients with paralytic polio may need physical therapy, crutches, leg braces, or surgery to help them regain their strength and movement.

What Should People with Poliomyelitis Expect?

Polio Around the World

In 2012 the World Health Organization (WHO) believed that polio was on its way to being eradicated from the Earth, because there were no new cases reported from January 2012 until April 2013. The organization's hope was premature. A resurgence of polio occurred after April 2013, leading to 417 cases of polio worldwide in 2013.

The WHO continued to emphasize the importance of vaccination, and implemented the Global Polio Eradication Initiative. As of August 1, 2015, it had been one year since the last wild polio case was detected on the entire African continent. A polio-free Africa would leave only two countries where polio transmission has never been interrupted: Pakistan and Afghanistan. WHO's new goal is a polio-free world by 2018.

Although a diagnosis of paralytic polio is a frightening one, most survivors go on to lead fulfilling lives. The violinist Itzhak Perlman, who caught the virus at four years of age and wears leg braces, is one example. Franklin D. Roosevelt, who got polio at the age of 39, went on to become president of the United States.

How Can Poliomyelitis Be Prevented?

The polio vaccine is the best way to prevent the disease, and its use has eliminated polio from the United States and much of the world. A worldwide vaccination program has been put in place, but the disease persists in such places as Afghanistan, India, Pakistan, and numerous countries in Africa. In many of these countries, poor sanitation and crowded conditions contribute to the spread of the disease just as health officials are trying to get everyone immunized.


Franklin Delano Roosevelt (FDR, 1882–1945) contracted polio at the age of 39 while vacationing on Campobello Island in New Brunswick, Canada. After a day of swimming and playing with his children, he went to bed tired and aching, and awoke unable to move his legs. Two weeks later, doctors identified his illness as polio. Roosevelt never walked unassisted again.

When he contracted polio in 1921, Roosevelt had already begun a life in politics, and he did not let the disease stop him. In 1932 he ran for the presidency of the United States and won. Although FDR did not try to hide his bout with polio, he went to great pains to disguise the extent of his disability. The public never saw him in his wheelchair. In 1938 FDR established the March of Dimes, which funded the research and immunization effort that eliminated polio from the Americas.

In 1998 a sculpture of Roosevelt in his wheelchair was added to the FDR memorial in Washington, DC. Depicting him this way was controversial. Some people felt that he would not have liked being shown in his wheelchair in the sculpture. Others argued that he would be glad to have his image encouraging people with disabilities to accomplish great work.

In the early 21st century, IPV was the only polio vaccine used in the United States, and it does not cause VAPP. Children might have a sore spot where they receive the shot, but side effects from the vaccine are very rare. Children receive IPV routinely as part of the childhood immunization schedule. Most adults who were vaccinated as children do not need to receive the vaccine again. People traveling to places where polio is still found (such as Africa and Asia); lab workers who handle poliovirus; and medical professionals who care for patients with polio may need a repeat vaccination. If polio is wiped out worldwide, then immunization against polio will no longer be needed.

See also Meningitis • Paralysis • Vaccines and Immunization • Viral Infections


Books and Articles

Groce, Nora Ellen, Lena Morgan Banks, and Michael Ashley Stein. “Surviving Polio in a Post-Polio World.” Social Science & Medicine. April 2014: 171–78. http://www.sciencedirect.com/science/article/pii/S0277953614001282 (accessed March 12, 2016).

Williams, Gareth. Paralysed with Fear: The Story of Polio. London: Palgrave Macmillan: 2015.


Centers for Disease Control and Prevention. “Polio Eradication.” http://www.cdc.gov/polio (accessed March 12, 2016).

MedlinePlus. “Polio and Post-Polio Syndrome.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/polioandpostpoliosyndrome.html (accessed March 12, 2016).

World Health Organization. “Poliomyelitis (polio).” http://www.who.int/topics/poliomyelitis/en/ (accessed March 12, 2016).


Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30329-4027. Toll-free: 800-232-4636. Website: http://www.cdc.gov (accessed March 12, 2016).

Immunization Action Coalition. 2550 University Avenue West, Suite 415 North, St. Paul, MN 55114. Telephone: 651-647-9009. Website: http://www.immunize.org (accessed March 12, 2016).

March of Dimes. 1275 Mamaroneck Ave., White Plains, NY 10605. Telephone: 914-997-4488. Website: http://www.marchofdimes.org (accessed March 12, 2016).

World Health Organization. Avenue Appia 20, 1211 Geneva 27, Switzerland. Telephone: 41-22-791-21-11. Website: http://www.who.int/en/ (accessed March 12, 2016).

* vaccination (vak-sih-NAY-shun), also called immunization, is giving, usually by an injection, a preparation of killed or weakened germs, or a part of a germ or product it produces, to prevent or lessen the severity of disease caused by that germ.

* enterovirus (en-tuh-ro-VY-rus) is a group of viruses that can infect the human gastrointestinal tract and spread through the body, causing a number of symptoms.

* brain stem is the part of the brain that connects to the spinal cord. The brain stem controls the basic functions of life, such as breathing, heart rate, and blood pressure.

* epidemic (eh-pih-DEH-mik) is an outbreak of disease, especially infectious disease, in which the number of cases suddenly becomes far greater than usual. Usually epidemics are outbreaks of diseases in specific regions, whereas widespread epidemics are called pandemics.

* cerebrospinal fluid (seh-reebro-SPY-nuhl floo-id) is the fluid that surrounds the brain and spinal cord.

* ventilator (VEN-tuh-lay-ter) is a machine used to support or control a person's breathing.

* pneumonia (nu-MO-nyah) is inflammation of the lungs.

* kidney stones are hard structures that form in the urinary tract. These structures are composed of crystallized chemicals that have separated from the urine. They can obstruct the flow of urine and cause tissue damage and pain as the body attempts to pass the stones through the urinary tract and out of the body.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)