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

Have questions about things like where to go for vaccinations or other health care services?

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Acute Flaccid Myelitis (AFM)
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Acute flaccid myelitis (AFM) is an illness characterized by acute onset of flaccid limb weakness and magnetic resonance imaging (MRI) showing lesions in the gray matter of the spinal cord. Additional symptoms in some patients include facial droop/weakness, difficulty moving the eyes, drooping eyelids, difficulty  with swallowing and slurred speech. Rare symptoms include numbness/tingling in the limbs, inability to pass urine, difficulty breathing due to muscle weakness requiring ventilator support.


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

  • polio enterovirus;
  • non-polio enteroviruses (e.g. enterovirus D68, A70, A71);
  • flaviviruses (e.g. West Nile Virus, Japanese Encephalitis Virus, Saint Louis Encephalitis Virus);
  • Herpes viruses (e.g. Cytomegalovirus and Epstein-Barr virus; and
  • Adenoviruses.

AFM may also be linked with environmental toxins and genetic disorders.


Transmission varies with the specific infectious agent.

Incubation Period:

Varies with the specific infectious agent.

Prevention and Vaccination:

For prevention of AFM regardless of etiology, observation of goof hand hygiene is recommended.

For known etiologies such as poliovirus, being current on all vaccinations is recommended. For protection against West Nile virus (WNV) associated AFM, prevent mosquito bites by using screens on windows, wearing protective clothing and mosquito repellent if outdoors and eliminating mosquito breeding sites.


Clinical diagnosis is made by reviewing neurological symptoms, examining brain and spinal MRIs, CSF testing and testing of nerve speed and response of muscles. 

To report a suspect case call:
Hotline: (888) 397-3993          Fax Line: (213) 482-5508
For guidance on specimen collection call:
Acute Communicable Disease Control: (213) 240-7941

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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