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.
The agency said 127 cases of acute flaccid myelitis have been reported so far in 2018. To date, 62 of those cases, from 22 states, have been confirmed; investigations of the others are ongoing.
The mysterious increase in cases of AFM, as it’s called, was first spotted in the late summer and autumn of 2014. There have been cases each year since, but the numbers have been higher on alternate years. This year is one of them.
Since the cases were first recognized in 2014, there have been 386 cases in the United States, Dr. Nancy Messonnier, director of CDC’s National Center for Immunization and Respiratory Diseases, told reporters. Most of the cases are in children under the age of 19, with kids under the age of 4 appearing to make up the biggest portion of cases.
“We have not been able to find a cause for the majority of these AFM cases,” Messonnier admitted. “There is a lot we don’t know about AFM, and I’m frustrated that despite all of our efforts, we haven’t been able to identify the cause of this mystery illness.”
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.
“We’re actually looking at everything. And certainly after three cycles of this, when we’ve looked through all the normal agents, we’re looking beyond that to see if there are things beyond normal infectious diseases that could cause this,” said Messonnier. “This is a mystery so far, and we haven’t solved it yet, so we have to be thinking broadly.”
AFM is a condition in which the gray matter of the spinal cord becomes damaged, leading to muscle weakness and paralysis in one or multiple limbs. Symptom onset is generally quite sudden, and Messonnier urged parents to seek medical care quickly for children displaying these symptoms.
In some cases children have recovered, but in others the paralysis has lingered.
Messonnier said the CDC has definitively ruled out polio — which causes a similar set of symptoms — as the cause. Testing of affected children has turned up a smattering of infections — some by enteroviruses, which is the broad family to which polioviruses belong, but also rhinoviruses, which cause head colds. No one finding can explain all the cases, she said.
Messonnier stressed that while she understands how frightening this situation is for parents, they should remember that the infections are, in fact, rare. 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.