The condition affects the gray matter area of the spinal cord and causes weakness in the body's muscles and reflexes.
Thirty-eight cases of AFM have been confirmed in the United States so far this year, according to the CDC.
The Minnesota Department of Health is investigating an outbreak of a rare, polio-like disease that's struck six children in the state since the middle of September. At his worst, the Youngs say, Orville was unable to move the upper part of his right arm and had difficulty moving his legs and sitting up.
The regular cases in Minnesota are of children under age 10. This condition is not new, but the increase in cases we saw starting in 2014 is new.
Even with extensive lab testing, AFM is hard to diagnose, because it so similar to other conditions, including poliovirus, West Nile virus and adenoviruses, the CDC reports.
"The cause of any individual case of AFM can be hard to determine, and often, no cause is found", the Washington State Department of Health said in a release on Wednesday.
Despite the increase, the condition is still considered very rare, occurring in fewer than one in a million people in the USA each year.More news: Delighted with the way Prithvi Shaw dominated on debut: Virat Kohli
"There were not necessarily a lot of cases that had been noticed before" 2014, said Jayne Griffith, the Minnesota Department of Health's senior epidemiologist.
"If their child gets an enteroviral infection, they need to look for symptoms such as sudden onset of arm and leg weakness, difficulty swallowing".
However, 11 of the Colorado cases of AFM have tested positive for EV A71, a rare type of enterovirus not usually seen in the US but instead in Asia and other parts of the world, according to Dr. Rachel Herlihy, the Colorado state epidemiologist. These cases coincided with a severe respiratory illness caused by enterovirus D68. The first of the six diagnoses was made in mid-September.
AFM is not known to be contagious, she said. While AFM doesn't have a cure, the symptoms can be treated and in most cases death can be avoided.
The children are from King, Pierce, Snohomish and Lewis counties, the health department said. "It's a very devastating situation".
Health officials are warning parents to be on the lookout for symptoms.
The patients' symptoms have been most similar to complications of infection with certain viruses, including poliovirus, non-polio enteroviruses, adenoviruses, and West Nile virus. "Since we don't see a clear association with all of our cases with a particular virus or pathogen, the best we can do right now is to make sure you are doing everything you can".