And for now, it's hard to say if 2018 will equal or surpass spikes seen in 2014 and 2016, Messonnier said, adding that state and federal health officials haven't finished the whole diagnostic algorithm for numerous cases reported over the past several weeks.
At least 65 more cases are under investigation, said Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases.
Acute flaccid myelitis, also called AFM, is a rare but serious condition that affects the nervous system and causes the muscles and reflexes to suddenly become weak, she said Tuesday. The disease is being called acute flaccid myelitis, or AFM, and although researchers suspect that it's caused by a virus, no virus has yet been discovered that's associated with the condition.
The spikes were significantly higher in 2014, 2016 and 2018-to-date than in 2015 or 2017.
Cases have been on the rise since 2014. Today, that's 22, as the CDC tracks up to 127 potential cases. But Messonnier cautioned that it would be "premature" to be confident that this year will be the same as the earlier years.
Because the disorder is rare - afflicting less than one in a million people - doctors weren't considering it initially, Hill said.
Some patients recover quickly, while others experience paralysis and require ongoing care.
Many local cases have been treated at Children's Hospital of Philadelphia.
Health Department: 7th Case Of AFM Diagnosed In Minnesota
The CDC also does not yet know who may be at a higher risk for developing AFM or the long-term consequences of the condition. Despite extensive laboratory and other testing, CDC has not been able to find the cause for the majority of the cases.
"It's rare, but certainly when you hear about it it's very scary for parents", CBS News medical contributor Dr. Tara Narula told "CBS This Morning".
"I am frustrated that despite all of our efforts we haven't been able to identify the cause of this mystery illness", she said.Although the cause remains a mystery in the majority of cases, the 2014 jump coincided with "a national outbreak of severe respiratory illness among people caused by enterovirus D68", though it wasn't found in all patients, according to the CDC. Some patients have tested positive for enterovirus or rhinovirus. But so far, no pathogen has been consistently detected in the patients' spinal fluid.
There is no treatment specifically for AFM, but affected children can undergo physical and occupational therapy to maximize their strength and adapt to their limitations.
AFM appears to target children at around age 4.
The CDC is actively investigating and monitoring disease activity and recommends taking standard prevention measures such as hand-washing, protecting oneself from mosquito bites and staying up-to-date on vaccinations. Some children paralyzed by AFM have eventually regained their ability to walk, but need time.
Other states with cases included Colorado, Illinois and Washington.
There is no known cause or treatment, a state Department of Public Health advisory said.
States are not required to provide this information to the CDC but have been voluntarily reporting their data.