The Centers for Disease Control and Prevention is alerting parents about a likely outbreak of a rare, life-threatening disease that targets children.
The potential outbreak can occur between the end of this summer and winter, reported the New York Post.
The illness is called acute flaccid myelitis (AFM) and CDC Director Robert Redfield shared that it "is a medical emergency that requires immediate recognition and care."
AFM is a rare neurological disease that affects the spinal cord and eventually can lead to paralysis.
Symptoms may include sudden arm or leg weakness, limb pain, difficulty walking, and back or neck pain. If the disease leads to paralysis, children could potentially need a ventilator for breathing.
Doctors say it mostly affects younger children. Experts are now warning parents if their child develops a sudden leg or arm weakness to seek medical help immediately.
Most children who experience AFM will have a respiratory illness or fever for about six days before weakness occurs.
Experts are unclear on why some children get AFM and why some don't.
"We've learned a lot, but we have a lot to learn about AFM ... We are working at CDC and collaborating with the NIH on a couple of prospective large studies, which will help us better understand risk factors for AFM," Redfield said.
The CDC began reporting cases of AFM in 2014 and have seen it peak every two years, typically in late summer to fall. In 2018, the United States experienced the largest outbreak of the disease, with 238 cases in 42 states between August and November. The average age was just five years old.
At least 98% of those children were hospitalized, and half of them were admitted to the intensive care unit. However, 20% required a ventilator to breathe.
According to the CDC, there have been 16 confirmed cases of AFM in 2020, reported NBC News.
Currently, there is no test or treatment for AFM.