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Frequently Asked Questions by Clinicians and Health Departments

Q: How can I send information about a case of AFM?

A: Clinicians: If you believe your patient has symptoms of AFM, contact your state or local health department as soon as possible for instructions on how to report. Urgent questions may also be directed to the CDC Emergency Operations Center (770-488-7100). Non-urgent questions can be emailed to the AFM team at In addition, please collect biological specimens for testing as soon as possible to increase the possibility of finding a cause. These specimens can be tested at a hospital or state public health laboratory for enteroviruses, West Nile virus, and other infectious etiologies known to be associated with AFM. At the same time, additional aliquots of CSF, serum, stool, and respiratory samples should be sent to CDC for testing for both infectious and non-infectious causes. Additional instructions regarding CDC-specific specimen collection and shipping can be found at Specimen Collection Instructions.

Health departments: If you have received information about a suspect case of AFM, complete the patient summary form in conjunction with the clinician, collect the requested clinical information (i.e., admission and discharge notes, MRI report, MRI images, neurology consult notes, infectious disease consult notes, vaccination record, diagnostic laboratory results, and EMG report if done and available), and contact CDC (, to coordinate the case classification process.


Q: Should I send information about a suspected case of AFM even if his/her clinical specimen was negative for enteroviruses?

A: Yes, we encourage information about all suspected cases of AFM to be sent to the health department regardless of laboratory testing results. Although the outbreak of severe respiratory illness caused by enterovirus D68 (EV-D68) and the national cluster of AFM cases occurred around the same time in 2014, the pathogen or biologic mechanism responsible for the AFM cases has not been identified yet. We request information and biological specimens from ANY patient suspected of having AFM (an illness with onset of acute flaccid limb weakness), regardless of whether they test positive or negative for an enterovirus.


Q: Should I send specimens to CDC even if the hospital laboratory or state public health laboratory can test for enteroviruses?

A: Yes, we request that specimens (i.e., cerebrospinal fluid, serum, stool, and respiratory samples) be sent to CDC for standardized testing and for our expanded testing protocols. Contact your health department to coordinate sending of specimens to CDC for testing. Results from certain tests, such as enterovirus/rhinovirus testing and typing and stool testing, will be shared with the health department upon completion. The health department will then share the results with the clinician. For instructions on how to submit specimens to CDC, see Specimen Collection Instructions.


Q: What happens to the patient specimens that I send to CDC, and when should I expect to receive the testing results?

A: All specimens submitted to CDC help us learn more about AFM, including possible causes and how the immune system responds to this condition. Results from these tests should not be used to inform clinical management of your patient because results may not be available in real-time. Results from the respiratory testing for enterovirus/rhinovirus and typing and stool testing for poliovirus will be shared with the specimen submitter and health department as soon as they are completed. The health department will then share the results with the clinician. Results from other specimens (e.g., CSF and serum) will be used for exploratory testing to learn more about immune responses to AFM, and results will not be immediately available. Since CDC testing protocols include several immunoassays that are not approved by the Clinical Laboratory Improvement Amendments (CLIA) nor are intended for clinical diagnosis, CDC will be unable to provide patient-specific results for certain tests that are performed. However, results from exploratory testing of samples from multiple cases which may indicate a possible cause of AFM will be rapidly disseminated.


Q: When should I expect AFM case classification results back from CDC?

A: The process for case classification requires collection of many different pieces of information, including hospital notes and MRI images, which are then reviewed by several experts. Case classification is used for surveillance purposes and should not interfere with the differential or final clinical diagnosis or treatment of the patient. The case classification will be communicated through the state or local health department when the review is complete, generally about 4 weeks after all of the information is received.


Q: Will CDC conduct extended follow-up on cases of AFM after their initial clinical presentation?

A: Currently, we are working with health departments to collect short-term follow-up information (2 months after onset of limb weakness) about suspected cases of AFM. The health department may reach out to the treating clinician to collect this information. We conducted a short-term follow-up survey on cases with information collected during the 2014 investigation, and received responses from roughly half (56) of the identified cases. A small number described complete recovery of limb function after a median of about 4 months after onset of limb weakness. The majority described some improvement of function. A small number described no improvement in limb function. Information on long-term follow-up conducted on AFM cases from Colorado that occurred in 2014 can be found at:


For more information on AFM, visit For Clinicians and Health Departments.