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 its destruction to the nervous system, causing paralysis. The majority of individuals who are infected with polio, however, have no symptoms and few have mild symptoms. Of those persons that do acquire the infection, 5 percent or fewer may develop paralytic disease. Since the advent of the polio vaccine during the early 1950's, infections from the poliovirus have nearly been eradicated. In the US, 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 (WHO) continues its efforts to eradicate the virus worldwide.

The last case of naturally occurring polio infection in the US 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 handwashing 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 (90 to 95 percent) have no symptoms at all. This is referred to as inapparent infection. The three other categories will be discussed.

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 (up to 103°F or 39.5°C)
- decreased appetite
- nausea and/or vomiting
- sore throat
- not feeling well all over
- constipation
- abdominal pain
nonparalytic poliomyelitis
The symptoms for nonparalytic poliomyelitis are the same as abortive poliomyelitis but the headache, nausea, and vomiting may be worse. In addition the following symptoms may occur:
- the child 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
- weak cough
- flushed or blotchy skin
- hoarse voice
- bladder paralysis
- muscle paralysis

How is poliomyelitis diagnosed?

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

cultures of the throat, urine, and stool
lumbar puncture or spinal tap
history of child not receiving the polio vaccine or not completing the series of polio vaccines

Treatment for poliomyelitis:

Specific treatment will be determined by your physician 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 cure for individuals who become infected. Treatment is supportive which means that the symptoms may be treated to improve comfort and recovery for the patient.

treatment of pain with analgesics (such as acetaminophen)
bed rest until fever is reduced
proper diet
minimal exertion and exercise
hot packs or heating pads for muscle pain
hospitalization may be required for those individuals who develop paralytic poliomyelitis
complications of paralytic poliomyelitis may include permanent paralysis of certain muscle groups including breathing muscles and leg muscles

Preventing poliomyelitis:

good hygiene and handwashing
immunization against poliovirus: In the US, 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.
- 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 Centers for Disease Control and Prevention (CDC), Advisory Committee on Immunization Practices (ACIP), and American Academy of Pediatrics (AAP) has recommended that the OPV not be given routinely and that only IPV be given. There are situations when it may be necessary for your child to receive OPV such as travel to countries where infectious or "wild" poliovirus may be communicable.
- Oral Polio Vaccine should NOT be given to a child if they have any of the following:
  - weakened immune systems
  - are taking long-term steroids
  - has cancer
  - has AIDS or HIV infection
  - allergies to neomycin, streptomycin, or polymyxin B