'Medical mystery' still stumps doctors amid outbreak of poliolike paralysisWhen 13-year-old Billy Sticklen woke up the morning of Sept. 24, he discovered he couldn’t lift his arms above his chest. Within days his paralysis had progressed to the point where he could only move his hands and feet. Now, with intensive physical therapy, he’s been making steady progress, moving from a wheelchair to a walker, and just days ago to walking with a cane. Researchers once thought they might have an explanation for why this Joplin, Mo., boy and more than 100 other children from across the country have developed this poliolike paralysis since August. But as they collect more evidence, the cause has become less and less certain. “In fact, it’s a medical mystery,” said Mary Anne Jackson, chief of infectious diseases at Children’s Mercy Hospital.

Jackson and other doctors at Children’s Mercy were among the first in the nation to recognize that a virus called enterovirus D68, or EV-D68, once considered rare, was causing an outbreak of often severe respiratory illnesses among children last summer. Since August, the Centers for Disease Control and Prevention has counted more than 1,100 confirmed EV-D68 cases nationwide, almost all among children, many who had a history of asthma. It’s possible that millions of kids with milder symptoms also became ill. “It was the largest outbreak of its type ever reported in the world,” Jackson said.

About the same time that EV-D68 was sweeping the nation, poliolike cases started appearing among children, first in Colorado and then in 33 other states. Researchers suspected a link between EV-D68 and the paralysis because there were initial signs that some of the paralyzed children had been exposed to the virus. EV-D68 is a distant cousin of the polio virus. But as researchers have sifted through the evidence, they haven’t been able to establish that connection. “Today, there is no association” between EV-D68 and the paralysis, Jackson said. “We just don’t have any evidence that these two things go together.” Jackson wouldn’t say that EV-D68 has been ruled out entirely as a cause, but research into these paralysis cases has broadened considerably. Billy Sticklen’s case suggests just how easy it might be to look at EV-D68 as a suspect. More