Mysterious Polio-Like Illness In Maryland, 35 Other States

MARYLAND — Public health officials remain perplexed about a mysterious paralyzing illness — acute flaccid myelitis, also known as AFM — that is occurring in record numbers this year. More than 150 children in 36 states have come down with the polio-like illness, including three in Maryland, the Centers for Disease Control and Prevention said this week.

It’s unclear what is causing the illness that leaves some children unable to move their face, neck, back, arms or legs, the CDC said in a conference call with reporters on Monday, Dec. 10. Symptoms tend to appear about a week after children have had a fever or respiratory disease.

No one has died this year, but AFM was linked to one death in 2017 and it may have caused other deaths in the past, the CDC said.

Health officials have ruled out polio virus as a cause of AFM, but say the mysterious illness can be just as devastating as the disease that once struck tens of thousands of U.S. children a year, resulting in lasting paralysis for some. The difference is that most kids who contract AFM do recover, the CDC said. Polio was virtually eliminated after the introduction of a polio vaccine that became available in the 1950s.

The agency said there have been 158 confirmed cases of AFM this year, but public health officials are investigating almost double that number — 311 — of suspected AFM cases.

In October, Maryland health officials were reportedly investigating five cases of possible AFM. As of Dec. 10, the CDC reports there have been three confirmed cases in the state.

For an illness to be confirmed as AFM, the diagnoses must include an MRI scan that show lesions in the part of the spinal cord that controls muscles, the CDC said.

RELATED: 5 Cases Of 'Polio-Like' Illness Suspected In Maryland

About half the kids who have come down with the mysterious illness this year were admitted to hospital intensive care units and hooked up to machines to help them breathe, the CDC said.

In 2012, three cases of limb weakness were reported in California, but the first real wave of the illness occurred in 2014, when 120 cases were reported. In 2016, there 149 cases. The number of cases was significantly lower in 2015 and 2017 — another head-scratcher for public health officials.

The wave of AFM illnesses in 2014 corresponded with a virus called EV-D68. That “remains the leading hypothesis,” said Dr. Ruth Lynfield, one of a 16-member task force the CDC appointed to investigate AFM.

But there’s some disagreement among the medical detectives. There have been waves of AFM in years when the EV-D68 virus wasn’t active, and testing doesn’t confirm the presence of the virus in every case. Also, EV-D68 infections aren’t new in kids, and many Americans carry antibodies against it — so why would the virus suddenly cause a paralyzing illness?

“This is a key question that has confounded us,” said the CDC’s Dr. Nancy Messonnier, who is overseeing the agency’s investigation into the outbreak.

Equally mysterious is why AFM cases surge in two-year cycles. And here’s another wrinkle: More than 17 countries have reported scattered AFM cases, but haven’t seen the same cyclical surges reported in the United States.

When there is a wave of cases in the United States, they typically spike in September and taper off significantly by November. The problem has peaked this year, but the CDC said last week but the number of cases could go up as investigators continue to look at not-yet confirmed cases.

The states with the greatest number of AFM cases this year are Texas (21) and Colorado (15), but the state tallies may not truly represent where the illnesses are happening. Colorado was hit hard in the 2014 outbreak, and doctors there may simply do a better job of diagnosing the illness, the CDC said.

The Associated Press contributed to this report.

— By Patch editors Beth Dalbey and Elizabeth Janney.

Image: This 2014 file electron microscope image made available by the Centers for Disease Control and Prevention shows numerous, spheroid-shaped Enterovirus-D68 (EV-D68) virions. Doctors have suspected a mysterious paralyzing illness, acute flaccid myelitis, might be tied to the virus. This year has seen a record number of cases of the mysterious paralyzing illness in children, U.S. health officials said Monday, Dec. 10, 2018. (Cynthia S. Goldsmith, Yiting Zhang/CDC via AP, File)