Children's Hospital Colorado reports that, as of Friday, 11 children in Colorado have been hospitalized with partial paralysis.

Doctors aren't sure what is causing the illness which, according to CNN, includes symptoms such as limb weakness, cranial nerve dysfunction, and abnormalities in spinal gray matter. Four children in Boston reportedly also match the symptoms of the unknown illness.

KSBW reports some of the children in both Colorado and Boston have tested positive for enterovirus D68, a rare respiratory virus that has sent hundreds of kids around the country to the hospital. However, signs of the virus were not found in all of the children suffering from partial paralysis.

Dr. Samuel Dominguez of the Children's Hospital said, "It's probably going to be weeks to months in terms of trying to understand what's happening."

[image via Twitter.]