SEATTLE -- Centers for Disease Control and Prevention confirmed Friday that eight of nine children hospitalized with an acute neurologic illness have a rare disorder called "Acute Flaccid Myelitis" or AFM at Seattle Children's hospital.

Officials said the children arrived with their symptoms and did not acquire AFM at the hospital.

Scientists at the CDC are working to determine the exact cause of AFM.

The children range in age from 3 to 14 years old, and came from four Washington counties: King, Pierce, Franklin and Whatcom.

The CDC also determined that Daniel Ramirez, a Bellingham boy who died from a mysterious illness Sunday, did not have AFM.

AFM affects a person’s nervous system, specifically the spinal cord. AFM can result from a variety of causes, including viral infections, according to the CDC. Symptoms typically include sudden weakness in one or more arms or legs, loss of muscle ton, and decreased or absent reflexes.

The health department says many viruses and germs are linked to AFM, including common germs that can cause colds and sore throats, and respiratory infections. It can also be caused by poliovirus and non-polio enteroviruses, mosquito-borne viruses such as West Nile or Zika, and autoimmune conditions.

Washington Department of Health officials have set up a webpage on the AFM investigation.

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