Colorado had the second-highest number of cases of a mysterious paralyzing illness this year — topped only by Texas — but none of the cases were in El Paso County, officials say.

Nearly all 16 “confirmed and probable” cases of acute flaccid myelitis were reported in the Denver metro area, said Rachel Herlihy, a state communicable disease epidemiologist.

It’s still not entirely clear what’s causing people — mostly kids — to lose the ability to move their face, neck, back, arms or legs. The symptoms tend to occur about a week after the children had a fever and respiratory illness.

No one has died from the rare disease this year, but it was blamed for one death last year and it may have caused others in the past. This year’s confirmed cases are in 36 states.

The polio-like illness is associated with some rare forms of enterovirus, says the Colorado Department of Public Health and Environment.

“Enteroviruses are common, and they typically cause cold-like illnesses — things like hand, foot and mouth disease, diarrhea, skin rashes,” Herlihy said.

Illness, Sick, Photo Credit: champja (iStock).

Photo Credit: champja (iStock).

“Enterovirus A71 and another enterovirus you may have heard about, enterovirus D68, are both less common types of enteroviruses in the U.S. Most of the time, even those two rarer types will cause mild illness, but rarely, they can cause severe illness, including neurologic illness, that’s not typically seen with other enteroviruses.”

Forty-two people came down with enterovirus A71 this year, which caused “a broader spectrum of neurologic illness,” including meningitis, encephalitis and 12 of the cases of AFM, Herlihy said. Of the other four with AFM, one tested positive for enterovirus D68 and three tested negative for enteroviruses.

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Although federal Centers for Disease Control and Prevention officials say many children have lasting paralysis, those in Colorado appear to be recovering fully, Herlihy said. That could be attributed to the prevalence of A71 instead of D68.“It does appear that children who are infected with enterovirus A71 do seem to recover more completely, more fully than children who are infected with enterovirus D68,” Herlihy said. “In previous years when we detected enterovirus D68, we did have much higher rates of persistent weakness or paralysis in children.”

Herlihy said she doesn’t expect this year’s total to rise.

“There is an enterovirus season, just like there’s an influenza season, and that enterovirus season is typically late summer to early fall,” Herlihy said. “There might be lags in diagnoses or testing that occurs, but we really don’t expect additional cases to occur at this point.”

Gazette reporter Liz Forster and The Associated Press contributed to this report.