Acute flaccid myelitis (AFM) is a rare condition.
AFM affects the nervous system, specifically, the central region of the spinal cord which is filled with grey matter-a type of nerve cell.
Health officials say they do not yet know the long-term effects of AFM.
Investigators are still collecting data on the two unconfirmed cases in Minnesota, which involved children under the age of 10 who displayed symptoms in the summer, Griffith said.
On Monday, news broke that six children in Minnesota have been infected with the rare disease that causes lowered mobility or paralysis in the arms and legs. However, the 2014 cases coincided with a national outbreak of a respiratory illness caused by a virus called enterovirus D68.
Some affected by AFM may also be unable to pass urine, and have difficulty breathing, requiring urgent ventricular support. From August 2014 through August 2018, the CDC has been notified of 362 cases of the illness, mostly in children.
Much is still unknown about AFM and often, a cause for AFM can not be identified. It's possible that AFM has a variety of causes, including viruses (such as poliovirus and enteroviruses), environmental toxins and genetic disorders, the CDC says. "In addition to investigating the outbreak, the state health department has issued alerts to health care providers on how to test for the viruses and enhanced guidance to child care centers on infection prevention". Doctors stress that the early signs of AFM should be recognized and treatment should be started as soon as possible to prevent from severity of disease.
The disease usually presents itself at the end of a cold and then causes muscle weakness. The CDC has not identified a germ that has been consistently found in every case of AFM, according to its website.
"We don't yet have any effective treatment for the virus or for the condition", Messacar said.
Colorado has had 14 AFM cases so far this year, state epidemiologist Rachel Herlihy, MD, MPH, told NBC News.
Symptoms may include muscle weakness in the arms, legs and neck.