Health officials said five kids in Maryland are believed to have contracted a virus this fall that has symptoms similar to polio.

The state’s health department said the five reported cases of acute flaccid myelitis (AFM) also are being investigated by the U.S. Centers for Disease Control and Prevention, and are among dozens of cases the federal health agency is looking into across the country.

In an email Tuesday, Maryland Department of Health spokeswoman Brittany Fowler said the CDC will “make a determination about the status of the cases” in Maryland “based on clinical and laboratory information.”

The CDC referred calls to individual state health departments.

Kate Fowlie, a spokeswoman for the CDC, said in an email that many states are voluntarily reporting their data on the disease and that “many parents are coming forward to tell their stories.”

Maribeth Brewster, the director of the Virginia Department of Health, said no known cases of AFM have been reported in the commonwealth. Three cases of the disease were confirmed in the state in 2016.

Tom Lalley, the director of the D.C. Office of Communications and Community Relations, said there were no known cases of AFM among District residents in 2017 or 2018.

Maryland health officials said their first case was reported Sept. 21.

More than 120 confirmed or possible cases of the mysterious and rare condition have been documented so far this year, mostly since August, a top federal health official said Tuesday.

That’s up from 22 people who were said to have it in 2015. Most of the cases involve children, officials said.

In 2014 the CDC said there was a spike in the AFM virus, with 120 people afflicted with it from August to December of that year in 34 states.

AFM affects a person’s nervous system, according to the CDC website, mainly in the spinal cord, and can present polio-like symptoms, including weakness and pain in the arms and legs. Other symptoms may include trouble moving the eyes, drooping eyelids or facial droop and weakness. A person can also have slurred speech and problems with swallowing.

The cause of most of the AFM incidents is unknown, according to the CDC, as are the long-term effects. Officials said some patients diagnosed with AFM recover quickly, while others need ongoing care.

Benjamin Greenberg, a neurologist who has treated children with AFM at the University of Texas Southwestern in Dallas, said incidents of the disease appear to spike in the fall of even-numbered years, a pattern that began in 2014 and isn’t fully understood.

While AFM is “exquisitely rare,” Greenberg said, public health officials should consider developing a vaccine, and victims should prepare for extensive physical therapy — therapy that isn’t always covered by insurance. Some children paralyzed by AFM have eventually regained their ability to walk, but need time.

“Families really sticking with it are seeing slow but steady recovery,” he said.