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Acute Flaccid Myelitis

​Acute flaccid myelitis (AFM) is a rare but serious condition that affects the nervous system, mostly in children, causing weakness in the arms and legs. At this time the exact causes or source of AFM is unknown. Since August 2014, the Centers for Disease Control and Prevention (CDC) has seen an increased number of people across the United States with AFM.


Symptoms of AFM include sudden muscle weakness in the arms or legs. Some other symptoms that patients may have include:

  • Facial droop/weakness,
  • Difficulty moving the eyes,
  • Drooping eyelids, or
  • Difficulty with swallowing or slurred speech.

Parents who observe these symptoms of AFM should get their child to a health care provider immediately.

AFM in Pennsylvania

The Department of Health is working with the CDC to confirm diagnoses of AFM. As of May 23, 2019, the department is investigating the following cases:

  • 2019 - 1 confirmed case; 1 suspected case
  • 2018 - 11 confirmed cases; 0 suspected cases
  • 2017 – 1 confirmed case
  • 2016 – 7 confirmed cases
  • 2015 – 0 cases
  • 2014 – 7 confirmed cases
Case counts will be updated each Monday, as needed.

The source of most cases of AFM is unknown, however possible causes may include viruses, environmental toxins and genetic disorders, or an unknown combinations of factors.


While it is not known what is effective in preventing AFM, it’s always important to practice disease prevention steps, such as staying up-to-date on vaccines, washing your hands and protecting yourself from mosquito bites.

To learn more about AFM, visit the CDC’s website.