The Centers for Disease Control and Prevention expressed frustration and concern Tuesday about a puzzling surge in cases of polio-like paralysis, mostly in children, being reported across the country this year. Officials would not say what states they lived in, but cases have been reported in New York, Minnesota, Illinois, Colorado, and Washington. For example, 11 of the Colorado cases of AFM this year have tested positive for EV A71, a rare type of enterovirus not usually seen in the USA, rather in Asia and other parts of the world, according to state epidemiologist Dr. Rachel Herlihy.
Specifically, the disease affects the area of the spinal cord called gray matter.
Health experts say the disease can lead to paralysis and even death, but no deaths have been reported so far this year.
Standardized surveillance was established in 2015 to monitor this illness and attempt to estimate the baseline incidence.
The condition is not new, but officials started to see a rise in cases in 2014; and there was another spike in 2016. The symptoms tend to occur about a week after they had a fever and respiratory illness. In 2016, there were 149 cases.
Messonnier said the CDC has definitively ruled out polio - which causes a similar set of symptoms - as the cause.
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The other South Korean climbers who died have been identified as Lee Jaehun, Rim Il-jin, Yoo Youngjik, and Jeong Joon-mo. The climbers had been waiting for the bad weather to clear so they could begin their climb on the unsafe Himalayan peak.
A sharp spike in cases of pediatric acute flaccid myelitis, or AFM, is raising red flags with health officials, who despite concerted efforts, haven't identified a cause.
CNN reached out to health departments in every state; 48 states responded, plus the District of Columbia. A seventh case has been "clinically diagnosed", but remains under review by the CDC. In 2017, one person died of AFM.
Some victims have been infected with viruses, but researchers have been unable to identify a single virus responsible for all cases. That pattern appears to be repeating this year.
"We know this can be frightening for parents", Messonnier said. In particular, the condition can cause weakness in the arms and legs along with loss of muscle tone and problems with reflexes. "None of the specimens have tested positive for poliovirus". But that bug - enterovirus D68 - could not be definitively linked to the illnesses. The public health agency also does not fully understand long-term consequences or why some patients recover quickly while others continue to experience weakness.
Benjamin Greenberg, a neurologist who has treated children with AFM at the University of Texas Southwestern in Dallas, said AFM is "exquisitely rare". "We recommend seeking medical care right away if you or your child develop sudden weakness of the arms and legs".
She said it was important for parents and clinicians to remember that this is a rare condition, affecting less than 1 in 1 million people under 18. The disorder has been diagnosed in children who have received some of their recommended vaccinations and in unvaccinated children, she said.