Here is what is known about the disease that has had 127 confirmed or suspected cases in 22 states as of Tuesday, including Pennsylvania. Similar waves of the same illness occurred in 2014 and 2016.
"Right now, we know that poliovirus is not the cause of these AFM cases", Messonnier said.
So far, the CDC has found no relationship between vaccines and children diagnosed with AFM from the 2014 cases.
About 90 percent of the cases have involved paralysis, according to the CDC.
"This is a pretty dramatic disease", Messonnier said.
Health officials call the condition acute flaccid myelitis (AFM).
So far 62 of the cases-marked by sudden onset of limb weakness and decreased muscle tone-have been confirmed, Nancy Messonnier, MD, director of the CDC's National Center for Immunization and Respiratory Diseases, said today at a media briefing. But some states have previously announced clusters, including Minnesota, Illinois, Colorado, New York and Washington.
The CDC is actively investigating the cases and working with healthcare providers as well as state and local health departments to spread the word about AFM.
Dr. Mobeen Rathore, an infectious disease specialist at UF Health, told News4Jax on Tuesday that it's unclear whether any cases have been confirmed in Florida, but it is being investigated in the state. "There is a lot we don't know about AFM, and I am frustrated that despite all of our efforts, we haven't been able to identify the cause of this mystery illness".
Rathore said since its unclear what causes AFM, there is no treatment - it has to take its course on its own.
Wash your hands frequently to limit your exposure to germs. He also recommends getting the flu shot, although it won't prevent or cure AFM.
She said the CDC and research partners are casting a wide net trying to figure out what is causing the rise in cases, suggesting scientists have been looking at a variety of viruses and even environmental toxins in their search.
Most people infected with enteroviruses suffer only minor symptoms like cough and runny nose. AFM appears to be seasonal, occurring mostly in the late summer and fall, but appears in greater numbers every other year.
She added that confirmation of each case requires a review of MRI images and symptoms, "so there is going to be a bit of a lag as we confirm those things".
The CDC received information on 33 confirmed cases of AFM across 16 states in 2017, 149 cases in 39 states In 2016, 22 across 17 states in 2015 and 120 across 34 states in 2014.