Experts hunt for cause of rare polio-like illness
Scientists are studying whether the rare but paralyzing illness that has afflicted scores of children this year is linked to a respiratory virus that circulates in late summer and early fall.
The Centers for Disease Control and Prevention last week reported 386 cases of acute flaccid myelitis since August 2014. The illness mainly strikes children.
Cases are exceedingly rare; fewer than one in a million children are affected. But for a small number of children, the results are devastating.
It can paralyze a child’s arms and legs. Some who are stricken need ventilators to breathe. It can also cause muscle weakness, slurred speech and difficulty moving eyes and swallowing.
CDC officials have not identified what causes acute flaccid myelitis, or AFM. Although described as a polio-like illness, each confirmed case has tested negative for polio virus.
A strain of a respiratory virus called enterovirus has been detected in several cases, but health officials say they don’t have enough evidence to conclude a single culprit is responsible for AFM. They also are investigating whether genetic or environmental factors are involved.
“This is a mystery so far and we haven’t solved it yet,” said Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases.
The illness peaks every other year from late summer through early fall. Public health officials began tracking it in 2014 with 120 cases in 34 states. There were fewer than two dozen cases in 2015, but the illness surged again in 2016, with 149 cases in 39 states.
So far this year, 62 cases are confirmed in 22 states and another 65 suspected cases are being investigated, according to the CDC.
Priya Duggal,CQ a genetic researcher at the Johns Hopkins Bloomberg School of Public Health in Baltimore, is studying the illness.
“It seems to be cyclical – it’s every two years,” she said. “It’s pretty tragic to see these families and to talk to these parents and realize how much their lives have been upended.”
Duggal’s study of about 60 families compares the genetic profile of children and adults in families stricken with the illness. In some families, parents and siblings recovered quickly from minor symptoms while one child was paralyzed.