Acute Flaccid Myelitis (AFM)

Acute flaccid myelitis (AFM) is a rare but serious condition. It affects the nervous system causing the muscles and reflexes in the body to become weak. Most AFM cases occur in late summer and early fall between August and October. More than 90% of cases have been in young children.

Clinicians should report all patients suspected to have AFM, especially after respiratory illness or fever to Maine Center for Disease Control and Prevention (Maine CDC) as soon as possible.

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Symptoms of AFM


    The most common symptoms are arm or leg weakness and loss of muscle tone and reflexes.

Some people will also have:


Facial droop or weakness


Difficulty moving eyes or drooping eyelids


Difficulty swallowing or slurred speech

These symptoms can also include pain in the arms or legs. In rare cases people may also have numbness or tingling and/or be unable to urinate. Severe cases of AFM can cause issues with breathing or even death.


Possible Causes of AFM

  • Most patients with AFM had a mild respiratory illness or fever with a viral infection before they developed AFM.
  • It is unknown why a small number of people develop AFM after a respiratory illness.
  • Federal CDC has tested many specimens from AFM in attempt to determine the cause of AFM. For most cases, federal CDC did not find any pathogens in the spinal fluid.
  • All stool samples from AFM patients tested negative for poliovirus.

    Prevention of AFM

    Since the cause of AFM is unknown, there is no specific action to take to prevent AFM. You can decrease the risk of getting and spreading viral infections by:

  • Keeping up-to-date on all vaccinations
  • Washing hands with soap and water
  • Avoid touching your face with unwashed hands
  • Avoid close contact with people who are sick
  • Cleaning and disinfecting surfaces, toys, and doorknobs
  • Covering coughs and sneezes
  • Keeping sick children at home

    Resources for Parents

  • Factsheet for Parents External site disclaimer
  • Caring for Children with AFM External site disclaimer

  • AFM Toolkit for Providers

  • AFM Toolkit for Providers (8/23/2022)

    Additional Resources

  • Federal CDC's AFM Website External site disclaimer
  • AFM Fact Sheet (PDF) | (PDF) عربي | Français (PDF) | Lingala (PDF) | Português (PDF) | 中国人 (PDF) | Soomaali (PDF) | Español (PDF)