107 children stricken by mysterious polio-like illness

Doctors have more questions than answers about a mysterious polio-like illness that has paralyzed at least 107 children in 34 states since August.

The cases occurred around the same time that the USA was experiencing an outbreak of severe respiratory illness caused by enterovirus D68, which usually causes a mild illness similar to a cold.

This year, at least 1,153 people in 49 states and Washington, D.C., developed severe respiratory illnesses, according to the Centers for Disease Control and Prevention. Fourteen patients with the enterovirus died, although doctors can't say definitively that the virus caused their deaths.

A report from Children's Hospital Colorado found that five of 11 paralyzed children had the enterovirus in their noses or throats, although researchers can't say for sure that it caused the paralysis.

Doctors didn't find enterovirus D68 in spinal fluid. That would have been a strong sign that the virus caused the paralysis, says Samuel Dominguez, co-author of the new study. He is a pediatric infectious disease specialist at Children's Hospital Colorado in Aurora and at the University of Colorado School of Medicine.

The polio virus isn't always found in spinal fluid either. Dominguez says it's possible that doctors looked for the virus too late, after it had disappeared.

All the paralyzed children had a fever about a week before the paralysis developed, according to a report in The Lancet, which examined the cases of 12 children. Ten had damage to the nerve cells in their spine. Ten also had meningitis-like symptoms, including stiff necks and sensitivity to light.

They experienced different forms of paralysis. The paralysis tended to be on only one side of the body, like children disabled by polio, the study says. Ten of the 12 had weakness in their limbs, and six had weakness in the muscles needed to talk or swallow. Some had double vision.

"We're still hopeful there will be some improvement, but we're not expecting any dramatic recoveries," Dominguez says.

Although the condition caused children to develop extreme weakness in their muscles, they did not lose sensation in affected areas, he says. In fact, many of them had significant pain in the paralyzed limbs.

Only one of the paralyzed children nationwide has fully recovered, according to the CDC. None of the Colorado children has fully recovered.

In the worst cases, children are completely paralyzed, according to the CDC. Some have experienced paralysis of the muscles they need to breathe, causing them to be put on breathing machines.

Paralyzed children all had damage to nerve cells in the spine that control movement, according to the CDC. The paralysis set within a matter of hours.

Although viruses have caused sporadic cases of paralysis over the years, doctors haven't seen such a large outbreak, Dominguez says.

There is no approved medication for enteroviruses and no vaccine.

Although enterovirus 68 has been around since at least 1962, doctors don't know why it would suddenly be associated with so much illness, Dominguez says. "That's the big question: Why did it happen now? We don't really have an explanation. ... We don't really know what's going to happen this year. Was this a one-time thing? Or is it going to come back?"