The Centers for Disease Control and Prevention (CDC) has identified increased pediatric hospitalizations in patients with severe respiratory illness and

positive rhinovirus (RV) and/or enterovirus (EV) tests. RVs and EVs share clinically similar presentations and are indistinguishable from one another on multiplex assays often used in clinical settings. Further typing by CDC identified some specimens as positive for enterovirus D68 (EV-D68). Pediatric acute respiratory illness sentinel surveillance sites are also reporting a higher proportion of EV-D68 positivity in children who are RV/EV positive compared to previous years. Sentinel surveillance for EV-D68 at 5 hospitals with large pediatric units has been initiated in Wisconsin. Although it primarily causes acute respiratory illness, EV-D68 has been associated with acute flaccid myelitis (AFM).

AFM is a rare neurologic condition that results from inflammation of the spinal cord. Most cases of AFM experience sudden onset of arm or leg weakness with loss of muscle tone and reflexes. Some AFM cases may also experience facial droop, difficulty moving their eyes, drooping eyelids, pain in arms or legs, and difficulty with swallowing or speaking. Severe cases can result in respiratory failure and death. AFM can result from a variety of causes, including environmental toxins, viruses, and genetic disorders.

AFM is challenging to diagnose because it shares many of the same symptoms as other neurologic diseases, like transverse myelitis and Guillain-Barre syndrome. Therefore, it is important to conduct proper examinations and testing necessary to differentiate between AFM and other neurologic conditions. Viruses that can cause AFM or similar neurologic conditions are poliovirus and non-polio EVs, flaviviruses (for example, West Nile virus, Japanese encephalitis virus), and adenoviruses. Often, despite extensive laboratory tests, the cause of a patient’s AFM is not identified.

As of September 21, 2022, there have been 15 confirmed AFM cases out of 45 patients under investigation (PUIs) in 10 states this year, including one in Wisconsin. CDC, in cooperation with state and local health departments, has been tracking AFM since 2014 when the United States recorded its first significant increase in AFM cases. Overall, there have been 694 confirmed cases since August of 2014, all of which have been thoroughly investigated by CDC. Increases in AFM cases, mostly in young children, were identified in 2014, 2016, and 2018.

The Wisconsin Department of Health Services, Division of Public Health (DPH) has identified 17 confirmed and 6 probable case of AFM in Wisconsin residents since 2014 and will continue to investigate other potential cases. Of note:

• The majority of patients with confirmed AFM infection had a mild respiratory illness or fever consistent with a viral illness before the onset of limb weakness.
• Most patients developed AFM between August and November.
• Many viruses, including EVs and RVs, commonly spread in the U.S. at this same time of year.
• Respiratory symptoms and fever from viral infections (such as with EVs and RVs) are common, especially in children, and most people recover without developing AFM.
• Increases in AFM cases coincided with a national outbreak of severe respiratory illness caused by EV-D68 in 2014, and increased circulation of EV-D68 in 2016 and 2018.
• EV-D68 is the most common virus detected in specimens from patients with AFM, usually in respiratory specimens.
• AFM patients also have antibodies against EVs in their spinal fluid more often than those without AFM.

Reporting

AFM is a reportable condition in Wisconsin. Report all cases of acute flaccid limb weakness to the Wisconsin Division of Public Health (DPH) within 24 hours (after hours reporting not required) by calling the Bureau of Communicable Diseases (BCD) at 608-267-9003. A job aid is available from CDC to assist clinicians with reporting and specimen collection.

For each suspect case under investigation, BCD will request the following information:

• AFM Patient Summary Form
• Infectious disease and neurology consult notes (if available)
• History and physical (H&P)          
• MRI images and report                                    
• Diagnostic laboratory reports
• EMG report (if done)
• Vaccination record

Suspect cases of AFM will be submitted to CDC, who will determine the final case status (that is, confirmed, probable, and not a case).

Clinical Management 

While there are no evidence based guidelines for the management of AFM, an updated interim considerations for AFM clinical management is available from the CDC. 

Recommendations for health care providers

• Consider EV-D68 as a possible cause of acute, severe respiratory illness (with or without fever) in children. Adults may also become infected with EV-D68, but it is thought to be more commonly detected in adults with underlying conditions.
• Consider laboratory testing of respiratory specimens for RVs and EVs (typically part of multiplex respiratory assays) when the cause of respiratory infection in severely ill patients is unclear, if not already part of typical diagnostic routine.
• Provide supportive clinical management for RV or EV, including EV-D68. There are no available vaccines or approved antiviral treatments.
• Report clusters of severe respiratory illness to local and state health departments.
• Strongly consider AFM in patients with acute flaccid limb weakness, especially after respiratory illness or fever, and between the months of August and November 2022.
• Collect specimens from multiple sources (cerebrospinal fluid [CSF], serum, stool, and a nasopharyngeal [NP] or oropharyngeal [OP] swab) from patients presenting with possible AFM as early as possible and preferably on the day of onset of limb weakness.
• Coordinate with your state public health laboratory to send AFM specimens to CDC for AFM and polio testing.
• Maintain vigilance and report possible cases of AFM to the state or local health department using the patient summary form.

Specimen Collection and Testing

For testing at CDC, collect specimens from multiple sources (cerebrospinal fluid [CSF], serum, stool, and a nasopharyngeal [NP] or oropharyngeal [OP] swab) from patients presenting with possible 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 cause of AFM.  Detailed specimen collection instructions are available from CDC. Coordinate with the Wisconsin State Laboratory of Hygiene (WSLH) and DPH to ship samples to CDC. Because CDC testing protocols include several assays that are not Clinical Laboratory Improvement Amendments (CLIA) approved for clinical diagnosis, additional specimens for testing at commercial laboratories should be collected for clinical management. Furthermore, CDC test results will not be available in real time. 

Detailed specimen collection instructions, including specimen type, storage, and shipping, are available from CDC. Instructions for specimen submission:

1. Indicate AFM on the WSLH requisition form (general form or outbreak form).
2. Complete the AFM Patient Summary Form and submit to DPH.
3. Use the usual courier, or if no courier is available, use Gold Cross.
4. For questions call the WSLH customer service line at 1-800-862-1013.

For specific questions regarding this notice please contact the DPH Bureau of Communicable Diseases at 608-267-9003.