Acute Flaccid Myelitis (AFM)

As of July 09, 2019, IDPH is reporting the following number of patients under investigation and number of cases that are confirmed, probable, and not cases according to the Centers for Disease Control and Prevention (CDC) review of acute flaccid myelitis (AFM). IDPH is working with the health care providers to collect necessary information to send to the CDC for AFM case classification. The case reports are from northern and central Illinois, and all but one patient is under 18 years.  Specific location information is not available. 

Patients Under Investigation (PUI) in Illinois* Confirmed AFM Cases** Probable AFM Cases** Not Cases**
20 9 3 8

*The PUI number is the total number investigated in 2018 and 2019, and includes those that are confirmed, probable, and not cases.
**Reference the Case Definitions for a description of confirmed and probable case classifications.  Those determined to not be cases by CDC are those that either did not meet the case classification or those we did not receive adequate information for determining case classification.  

***CDC will make the final determination on AFM classifications and numbers are subject to change.***

What is Acute Flaccid Myelitis?

Acute flaccid myelitis (AFM) is a rare but serious condition that affects the nervous system, specifically the spinal cord, causing the muscles and reflexes in the body to work abnormally. This type of condition is not new. Anyone can get AFM or neurologic conditions like it. There are different possible causes, such as viruses, toxins, and genetic disorders.

What are the signs and symptoms?

Most patients will have sudden onset of limb weakness and loss of muscle tone and reflexes. Some patients also will experience:

  • facial droop/weakness,
  • difficulty moving the eyes,
  • drooping eyelids, or
  • difficulty with swallowing or slurred speech.

Numbness or tingling is rare in patients with AFM, though some patients have pain in their arms or legs. Some patients with AFM may be unable to pass urine. The most severe symptom of AFM is respiratory failure that can happen when the muscles involved with breathing become weak. This can require urgent ventilator support (breathing machines).

If you or your child develops any of these symptoms, you should seek medical care right away.

What causes AFM?

Acute flaccid myelitis can be caused by a variety of pathogens, including several viruses:

AFM is one of a number of conditions that can result in neurologic illness with limb weakness. Such illnesses can result from a variety of causes, including viral infections, environmental toxins, genetic disorders, and Guillain-Barre syndrome, a neurologic disorder caused by an abnormal immune response that attacks the body’s nerves. Oftentimes, however, despite extensive laboratory testing, a cause for AFM is unable to be identified.

How is AFM treated?

There is no specific treatment for AFM, but a neurologist may recommend certain interventions on a case-by-case basis.


In 2016, two confirmed cases of AFM were reported in Illinois. The Illinois Department of Public Health (IDPH) is re-emphasizing the importance of continued vigilance in identifying cases of AFM among all age groups, irrespective of enterovirus status. Reporting of these cases will help public health officials monitor for increases in this illness and better understand potential causes, risk factors, and preventive measures or therapies. We are asking all clinicians to report AFM cases to the local health department, governing the jurisdiction where the patient lives.


Acute Flaccid Myelitis Case Definition

Clinicians suspecting AFM in patients meeting the probable or confirmed case definition (irrespective of laboratory testing results) are asked to report these cases to the local health department governing the jurisdiction where the patient lives, or to the Illinois Department of Public Health Communicable Disease Control Section at 217-782-2016. Clinicians should complete the patient summary form and submit it to their LHD as early as possible. Clinicians or infection control practitioners that have access to enter reportable diseases into the Illinois National Electronic Disease Surveillance System (I-NEDSS) should also enter the case’s information into the system’s AFM module. Local health departments (LHD) should report AFM cases into I-NEDSS as an AFM case if the clinician has not done so.

Specimen Collection and Testing

Clinicians should collect specimens from patients suspected of having AFM as early as possible in the course of illness, preferably on the day of onset of limb weakness. Early specimen collection has the best chance to yield a diagnosis of AFM. CDC has specimen collection procedures on their website. Please refer to CDC’s collection procedures for the most up-to-date instructions. NOTE: specimen coordination should be done in conjunction with the LHD and/or IDPH CD section prior to shipment.

The following three forms must be completed and included with all specimen submissions to IDPH laboratory:

Medical providers and infection control practitioners should contact their local health department with questions about AFM reporting. Local health departments with questions should contact IDPH Communicable Disease Control Section at 217-782-2016.