There have been two confirmed cases of acute flaccid myelitis, or AFM, in MA this year.
The CDC has confirmed 62 cases across 22 states this year, compared with 33 cases last year, and is investigating dozens more reports.
That figure may seem small, but Friedman said Sick Kids normally sees only about two cases of AFM a year and the condition carries an annual incidence risk of about one case per million children.
"CDC is now providing the number of patients still under investigation so people can better anticipate increases in confirmed cases over the coming months", the agency said in a statement. "We are working closely with healthcare providers and state and local health departments to increase awareness for AFM".
During an information briefing, the Director of CDC's National Center for Immunization and Respiratory Diseases, Dr. Nancy Messonnier said, despite extensive laboratory testing, they don't know what causes the arm or leg weakness and paralysis in most patients.
The CDC has a hunch that AFM can be caused by other viruses like enterovirus or west nile virus. Children may also have trouble breathing, and in severe cases may require a ventilator due to muscle weakness. "What the physician will do is rule out other causes rule out other things that might be causing it".
AFM cases on the rise in the U.S. Story continues below video.
It's unclear what's causing the outbreak, which can develop after a viral infection, environmental toxins, and genetic disorders.
Messonnier said other viruses besides EV-D68 have been found in patients with AFM. "That is what we are not finding", she said. Those with spinal cord damage caused directly by the virus warrant different treatments and don't respond as well. However, they want to stress how rare this condition is. Zika is one of the most notorious recent examples. "We try to keep muscles and joints as healthy as possible so that when the nervous system is repairing itself, it will have adequate muscle to connect to", Greenberg said. These viruses caused symptoms including encephalitis, a life-threatening inflammation of the brain; acute flaccid paralysis, which can include AFM and similar conditions; and meningitis. Parents can also help protect their children by encouraging hand washing, staying up to date on recommended vaccines and using insect repellent to prevent mosquito bites.