So far this year, there have been 127 confirmed and suspected cases of acute flaccid myelitis, a condition in which one or more limbs becomes paralyzed, the Centers for Disease Control and Prevention reported in a news conference Tuesday (October 16). The incidences, 62 of which are confirmed, are spread across 22 states.
Acute flaccid myelitis (AFM) resembles polio in that it causes paralysis and mostly affects children, but the Centers for Disease Control and Prevention (CDC) has ruled out polio as a potential cause, STAT reports. “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,” Nancy Messonnier, director of CDC’s National Center for Immunization and Respiratory Diseases, told reporters, according to STAT.
In AFM, the gray matter of the spinal cord gets damaged, leading to muscle weakness and paralysis. It can start with a fever and respiratory illness; then the sick child suddenly loses the ability to move an arm or leg. Ninety percent of people with AFM are 18 or younger, and the average age of AFM patients is four years old, Buzzfeed notes.
Cases of AFM were first reported in 2014, and since then, incidences of the condition have been higher in alternate years, STAT notes. Fall 2018 represents the third surge of AFM cases, which seem to spike in late summer and early fall, as Buzzfeed notes.
“We are seeing more cases of this in the U.S. than we are seeing in polio in the whole world,” University of Colorado neurologist Kenneth Tyler tells Science. “You don’t need an awful lot of paralyzed children to make this an important problem.”
In 2014, the initial reports of AFM coincided with an outbreak of infections from an enterovirus, EV-D68, that causes a respiratory illness, according to the CDC. But the link between AFM and EV-D68 is unclear because not everyone who has AFM tests positive for the enterovirus. It’s possible that some patients had EV-D68, but were tested too late for the virus to show up in stool and respiratory samples, Science notes.
Tyler has found in the lab that strains of EV-D68 can paralyze mice, Science reports, and researchers are investigating the possibility that genetic factors could predispose people to paralysis after infection.
Parents should seek immediate medical care for kids exhibiting AFM symptoms, Messonnier said at the press conference, according to STAT. The benefit of seeking medical care is to attend to kids’ symptoms, which can include respiratory failure, Science News reports, but there is currently no cure for AFM.
Some patients have recovered movement; some have not. Regaining the ability to walk after AFM infection may take a lot of physical therapy, Benjamin Greenberg, a neurologist who has treated children with AFM at the University of Texas Southwestern Medical Center, tells The Washington Post.