Acute Communicable
Disease Control

Contact Information
County of Los Angeles
Department of Public Health
Acute Communicable Disease Control
313 N. Figueroa Street, #212
Los Angeles, CA 90012
Phone: (213) 240-7941
Fax: (213) 482-4856

Call 211 For Information 24/7

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Acute Flaccid Myelitis (AFM)
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Acute flaccid myelitis (AFM) is an illness characterized by a sudden onset of acute flaccid limb weakness without a known cause and magnetic resonance imaging (MRI) showing lesions in the gray matter of the spinal cord. Most cases are in children.


The agent is unknown, but most likely viral. The specific causes(s) are still under investigation and may include:

  • Non-polio enteroviruses (Enteroviruses D68, Enteroviruses A71, Coxackievirus A16).
  • Flaviviruses (West Nile Virus, Japanese Encephalitis Virus).
  • Herpesvirus


Varies with the specific infectious agent.

The most common symptoms include, a sudden onset of arm/leg weakness, loss of muscle tone and reflexes. Other symptoms include:
  • Facial droop/weakness
  • Difficulty moving the eyes/drooping eyelids
  • Difficulty in swallowing  or slurred speech
  • Pain in arms or legs
  • Pain in neck or back
The most severe symptoms of AFM are:
  • Respiratory failure
  • Serious neurologic complications such as body temperature changes and blood pressure instability

Incubation Period:

Varies with the specific infectious agent.


Since AFM can be caused by viruses, lower your risk of getting and spreading viruses by:

  • Regular handwashing with soap and water
  • Avoid touching face with unwashed hands
  • Avoid close contact with sick persons
  • Cleaning and disinfecting frequently touched surfaces
  • Covering coughs and sneezes
  • Staying home when sick


Clinical diagnosis is made by reviewing neurological symptoms, examining brain and spinal MRIs, Cerebrospinal Fluid (CSF) testing and testing of nerve conduction and response. 

Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.
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