There are now 62 confirmed reports of acute flaccid myelitis, or AFM, across 22 states in the US, according to the Centers for Disease Control and Prevention.
"They are generally seeking medical care and being evaluated by neurologists, infectious disease doctors and their pediatricians".
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.
CDC officials say they haven't found the cause.
"We're actually looking at everything". The Florida Department of Health said one case has been reported this year. For reasons not fully understood, AFM affects mainly children. But officials haven't been able to find a single agent that would explain the clusters of cases that occur around the same time.
There is no specific treatment for the disorder, and long-term outcomes are unknown. Working with local and state health departments and hospitals, the CDC has been able to confirm a number of these cases faster, she said. Cases have been reported from the Twin Cities, central Minnesota and northeastern Minnesota. Since the phenomenon began in 2014, she said, the rate of infections has been less than one case per 1 million children in the country.
About 90 percent of the cases are children who have suffered muscle weakness or paralysis.
Some patients diagnosed with this condition have recovered quickly, but some continue to have paralysis and require ongoing care, she said.
There are five cases of AFM in Maryland. Then in 2016, there were 149 confirmed cases. Officials said it's too early to know whether the total cases for 2018 will surpass those previous years. But the data reported Tuesday represents "a substantially larger number than in previous months this year", Messonnier said. "As a parent myself, I understand what it's like to be scared for your child", she said.
More broadly, she noted, "there is a lot we don't know about AFM".
The mysterious increase in cases of AFM, as it's called, was first spotted in the late summer and autumn of 2014. The CDC stressed that none of the children who developed these symptoms had the polio virus. Messonnier added that health officials are considering other potential causes, such as West Nile virus and environmental toxins, though none of the cases have involved them. Another kind of virus is suspected, but it's been found in only some of the cases.
While AFM is not unique to the US, Messonnier said, "no one else has seen seasonal clustering every other year". CDC has tested many different specimens from patients with this condition for a wide range of pathogens, or germs, that can cause AFM.
The CDC is investigating the cases and monitoring the disease, and encourages people to prevent the disease by staying up to date on vaccines, washing hands and protecting against mosquito bites. Specifically, the disease affects the area of the spinal cord called gray matter.
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.
So far, the CDC hasn't seen any geographic patterns based on reporting from states.