Over the last couple of weeks, medical professionals at Children's Hospital in Seattle and in 23 other states have been grappling with a mysterious medical issue, possibly a disease that's very rare. But it could be causing a series of illnesses, one of them fatal.

State Department of Health officials Tuesday released more information about 9 people in Washington state (part of at least 50 in 24 states) who have been afflicted with symptoms that could indicate they have AFM, or Acute Flacid Myelitis.  Officials say the children, ages 3 to 14, including two from Franklin County, have become sick with symptoms consistent with that ailment. 1 child has already died from complications, but that child was not officially diagnosed with AFM.

9 cases have been reported, 2 officially diagnosed as AFM, seven others still being investigated. Three are in King County, 1 in Pierce and Snohomish Counties, and two in Whatcom County. It is not yet known what may have caused these illnesses.

AFM is a neurological disease that affects muscles, reflexes and is centered in the spinal chord. It can come from viral infections. It's marked by sudden weakness in one or more arms, loss of muscle tone, decreased reflexes. In some cases difficulty swallowing, droopiness of eyes, and dysfunction of the nerves in the neck may also be present. It's a very rare disease, no cases reported in WA state last year, only two in 2014.

For more information and the latest updates, the Department of Health has posted a website page for the public.