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.
The CDC will determine whether the suspected cases in Maryland are AFM based on clinical information and lab tests, a spokeswoman for the state health department said in an email. Since 2014, 386 cases have been confirmed, the CDC said on Tuesday. More than 90 percent of the confirmed cases have been in children 18 and under, with the average age being 4 years old.
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.
"Right now, we know that poliovirus is not the cause", Messonnier said, dispelling reports that AFM was possibly linked to polio. But officials haven't been able to find a single agent that would explain the clusters of cases that occur around the same time. The disease affects the body's nervous system and can cause paralysis. Other symptoms may include trouble moving the eyes, drooping eyelids or facial droop and weakness. "Most AFM cases occur in the late summer and fall", which she referred to as "seasonal clustering".
"What parents have to know is if your child suddenly has a weak arm or leg, is not speaking properly, has a stiff neck or a wobbly neck - call the doctor immediately", pediatrician Dr. Laura Popper said.
Besides viruses, officials are also considering environmental toxins as a possible cause, but so far, they have no evidence that a particular toxin is behind the cases.More news: O'Rourke evokes Trump's 'Lyin' Ted' in debate
MA has seen a total of 16 confirmed cases in children since 2014, plus one probable case in an adult.
After testing patients' stool specimens, the CDC determined poliovirus is not the cause of the AFM cases.
"As a parent myself I understand what it's like to be scared for your child", Messonnier said. What happens to patients down the line is unclear; some recover quickly, while others may need long-term care.
Officials said they will be conducting additional analysis on this year's cases. Health officials are alarmed and frustrated, because a specific cause hasn't been identified.
But Messonnier said that, in general, parents can help protect their children from diseases by washing their hands, making sure their children are up to date with vaccinations and applying insect repellent to protect against mosquito bites, which can spread viruses. "We recommend seeking medical care right away if you or your child develops sudden weakness of the arms and legs", she said.
States are reporting their cases to the CDC, Messonnier said.
About 120 confirmed cases were reported in 2014.