Poliomyelitis (Polio)

What is poliomyelitis (polio)?

Poliomyelitis is a highly contagious infectious disease caused by three types of poliovirus. The poliovirus is a virus most recognized for causing paralysis. According to the CDC, the majority of individuals who are infected with polio have no symptoms and a few have mild symptoms. Of those persons who do acquire the infection, 1 percent or fewer may develop paralytic disease. Since the introduction of the polio vaccine in 1955, infections from the poliovirus have nearly been eradicated. In the U.S., there have been no known infectious or "wild" cases of polio since 1979.

In countries that are poor, underdeveloped and do not have access to the vaccine, polio is still a concern, especially for infants and children. The World Health Organization continues its efforts to eradicate the virus worldwide:

  • The last case of naturally occurring polio infection in the U.S. was in 1979.

  • Infants and young children are at greatest risk.

  • Poliovirus infections are more common during the summer and autumn seasons.

  • The risk for paralysis from the virus increases with age.

How is poliovirus spread?

Transmission of the poliovirus most often occurs by the fecal-oral route. Usually this occurs from poor hand-washing or from ingestion of contaminated food or water. Respiratory secretions also spread poliovirus. Those infected with the virus can excrete the virus in their stool for several weeks. Individuals are most contagious immediately before the onset of symptoms and soon after they appear.

What are the symptoms of poliomyelitis?

Poliovirus infections can exhibit symptoms in varying degrees of severity. The majority of individuals have no symptoms at all. This is referred to as inapparent infection. The three other categories are discussed below.

The following are the most common symptoms of poliomyelitis. However, each person may experience symptoms differently. Symptoms may include:

Abortive poliomyelitis

A mild and short course of the disease with one or more of the following symptoms:

  • Fever

  • Decreased appetite

  • Nausea and/or vomiting

  • Sore throat

  • Not feeling well all over  (malaise) 

  • Constipation

  • Abdominal pain

Nonparalytic poliomyelitis

The symptoms for nonparalytic poliomyelitis are similar to abortive poliomyelitis but, in addition, the following symptoms may occur:

  • The infected person may feel sick for a couple of days then appear to improve before getting sick again with the following symptoms:

    • Pain of the muscles in the neck, trunk, arms, and legs

    • Stiffness in the neck and along the spine

Paralytic poliomyelitis

The symptoms for paralytic poliomyelitis are the same as nonparalytic and abortive poliomyelitis. In addition, the following symptoms may occur:

  • Muscle weakness all over

  • Severe constipation

  • Muscle wasting

  • Weakened breathing

  • Difficulty swallowing

  • Muscle paralysis (may be permanent) 

  • Drooling

How is poliomyelitis diagnosed?

In addition to a complete physical examination and medical history, the following tests may be completed:

  • Cultures of the throat, cerebrospinal fluid, and stool

  • Test for polio antibodies levels

  • Lumbar puncture or spinal tap

What is the treatment for poliomyelitis?

Specific treatment will be determined by your doctor based on:

  • Your age, health, and medical history

  • Extent of the disease

  • Your tolerance for specific medications, procedures or therapies

  • Expectations for the course of the disease

  • Your opinion or preference

While there is prevention of the poliomyelitis, there is no specific treatment for individuals who become infected. Treatment is supportive, which means that the symptoms may be treated to improve comfort and recovery for the patient. Supportive measures include:

  • Treatment of pain with analgesics (such as acetaminophen)

  • Proper diet

  • Minimal exertion and exercise

  • Hot packs or heating pads for muscle pain

How is poliomyelitis prevented?

  • Good hygiene and hand-washing

  • Immunization against poliovirus: In the U.S., the polio vaccine is recommended to be given at the following ages:

    • 2 months

    • 4 months

    • Between 6 and 18 months

    • Between 4 and 6 years

  • Two versions of the vaccine may be administered:

    • IPV. Inactivated Polio Vaccine is administered by injection (a shot). This vaccine is administered at all four immunization visits. Administration of the IPV cannot cause polio and is safe to use for individuals with weakened immune systems. Tell your health care provider if you have an allergy to neomycin, streptomycin or polymyxin B, as you may not be able to receive the IPV. 

    • OPV. Oral Polio Vaccine is administered by mouth. In rare cases, OPV has been known to cause vaccine-associated paralytic poliomyelitis (VAPP). As of January 2000, the CDC, Advisory Committee on Immunization Practices recommends that the OPV not be given routinely and that only IPV be given.

    • Oral Polio Vaccine should NOT be given to a person if he or she has a weakened immune system.