Poliovirus Infection

What is a poliovirus infection?

Poliovirus infection is a infectious condition caused by the poliovirus. This virus infects the nervous system and may lead to muscle weakness or paralysis (inability to move muscles at all). This condition is very uncommon as immunization has caused the virus to be eradicated from many countries. People who are not immunized against polio and who travel to areas where the poliovirus is still active have a risk of getting a polio infection. Children under 5 years of age are most commonly affected. Symptoms may include fever, sore throat, headaches and aching muscles. Some, but not all, people go on to develop muscle weakness. Poliovirus infection cannot be cured and the treatment usually only controls the symptoms. The outlook after a poliovirus infection depends on the severity of the symptoms, but it can cause permanent disability and death.

Risks

Polio is caused by the polio virus. The virus is transmitted through direct contact with an infected person or through infected mucus and feces. Although this virus has been removed from most countries in the world, episodes or outbreak of polio still occur. Outbreaks tend to occur more commonly in the summer months. Although people of any age group can become infected, children under the age of 5 years are most commonly affected. The people who are not vaccinated against polio and who travel to areas where poliovirus is still active are at risk of getting infected.

Symptoms

Early symptoms of a poliovirus infection resemble the flu and include fever, headache, vomiting, feeling ill and sore throat. These symptoms will often get better within a few days, and most people will have no further symptoms. If the virus spreads to the nervous system, it can cause muscle weakness in the legs, arms, back or neck. This can cause problems walking and completing tasks, and even difficulty breathing. Over time, this causes tight joints, shrinking of the muscles (atrophy) or even paralysis. Symptoms may come back years after the original infection, causing the post-polio syndrome.

Diagnosis

The diagnosis can be made based on the symptoms and physical examination when it is known that a person is not immunized and has been to an area where they may have been exposed to the virus. Blood tests for immune proteins which fight the poliovirus (antibodies) and a lumbar puncture (taking a sample of fluid from around the spinal cord) are often done to confirm the diagnosis and to investigate for the virus in the nervous system.

Treatment

There is no specific cure for poliovirus infection. Treatment aims to relieve symptoms. This may mean simple pain relief for headaches and muscle aches. People with ongoing muscle weakness may need physical therapy to help improve muscle strength. If the breathing muscles are affected and become weak, the affected person may need a machine to help with breathing.

Prevention

Poliovirus infection can be prevented through vaccination. It is important to keep to the recommended vaccination schedule.

Other names for poliovirus infection

  • Polio
  • Infantile paralysis
  • Poliomyelitis