Polio-like virus AFM remains rare, but cases increasing

Acute flaccid myelitis, or AFM, isn’t new, but in the past four years the Centers for Disease Control and Prevention started seeing a rise in cases of the poliolike disease.

The disease affects the spinal cord and brain stem, according to Ohio State University’s Wexner Medical Center.

“It occurs most frequently in children and young adults and is characterized by a quick-evolving paralysis, which can progress within four to seven days,” Dr. Jan Schwab wrote on the Wexner Medical Center’s website. “Typically, it’s flaccid, thus there is no muscle spasticity. It mimics other viral diseases known to affect the neurons in the spinal cord, such as the polio virus.”

The condition is rare, affecting less than one in a million people in the U.S., but starting in 2014, the CDC began to notice an increase in confirmed cases. That year there were 120 cases reported between August and December across 34 states.

Case numbers have been up and down since then. In 2015 there were 22 cases in 17 states. In 2016, 149 cases in 39 states followed by 33 cases in 16 states in 2017. As of Nov. 23, there have been 116 confirmed cases in 31 states.

The CDC note it is currently difficult to interpret trends of the AFM data.

“Collecting information about patients under investigation (PUIs) for AFM is relatively new,” the CDC stated. “There may initially be more variability in the AFM data from year to year making it difficult to interpret or compare case counts between years.”

There have been eight confirmed cases in Ohio so far this year. There were two each in 2016 and 2017.

According to Ohio Department of Health spokesperson J.C. Benton, cases have been confirmed this year in Columbiana, Coshocton, Cuyahoga, Lorain, Lucas, Mercer, Pickaway, and Warren counties.

Schwab said that a good proportion of AFM cases are linked to enterovirus infections, specifically the Type D68.

“In some patients, this enterovirus infection is associated with the development of an acute inflammation of the spinal cord (acute myelitis),” he wrote. “Thus, the flaccid paralysis is caused by an inflammation – mostly located in the gray matter of the spinal cord. The enterovirus D68 can be detected in respiratory material (sputum), feces or cerebrospinal fluid.”

Though AFM is polio-like, the cases are not caused by the poliovirus. All stool specimens received by the CDC have tested negative for poliovirus.

Benton added that there is no evidence the disease is contagious.

The CDC stated that viral infections such as from enteroviruses are common, especially in children, and most people recover. They don’t know why a small number of people develop AFM, while most others recover. The agency said it’s continuing its investigation.

Since seeing the increase in cases in 2014, the CDC has learned that more than 90 percent of AFM patients had a mild respiratory illness or fever consistent with a viral infection before they developed AFM.

Over the past four years, cases have been found in 46 states and Washington, D.C.

More than 90 percent of the cases involve children. All eight cases this year in Ohio are in children, ranging from less than 1 year old to 13 years old. Seven of the eight patients are male, according to data from the Ohio Department of Health.

Most patients had onset of AFM between August and October, when many viruses commonly circulate, including enteroviruses, and will be temporally associated with AFM, according to the CDC. In the Ohio cases so far this year, the onset range is Aug. 5 to Oct. 12, according Ohio Department of Health data.

Schwab wrote that treatment for AFM is symptomatic. This includes providing enough fluid and early access to rehabilitation.

As for treatment, Schwab said that they understand the disease to be caused by a virus infection, so immunization would be the most effective and casual preventative strategy, but to date there is no vaccine available.

“Parents can help protect their children from serious diseases by taking preventive measures like washing their hands, staying up to date on recommended immunizations and using insect repellent to prevent diseases transmitted through the bite of infected insects like mosquitoes,” Benton said.

Though AFM cases have increased nationally, Benton said seasonal flu is a much greater health risk for most families, including children.