Your three-year-old has a cold. She gets over it. You know the drill.
Except that this time, something different occurs — something unimaginably horrifying. Within 24 hours, a facial droop begins and slowly worsens, accompanied by difficulty walking and then, possibly, with swallowing and holding the head upright.
Acute flaccid myelitis (AFM) — myelitis meaning inflammation of the spinal cord — is characterized by a quick onset of muscle weakness in one or more limbs, along with evidence of spinal-cord motor neuron damage. It resembles polio not only in these symptoms, but in the age of its victims (mostly pre-teenagers) and its rate of untreated full recovery (two-thirds).
As in polio, the third who don’t fully recover run the gamut of affliction from minor lifelong disabilities to, in one case so far, death.
From August 2014 through August 2018, the Centers for Disease Control and Prevention (CDC) confirmed a total of 362 AFM cases across the United States. That’s about five in every million children, which makes it still extremely rare. However, the CDC believes the incidence of AFM is increasing slightly. It reported a nationwide spike in AFM cases this year, to 127 children — similar to spikes seen in 2014 and 2016.
In a scramble to identify any known or new viruses responsible, the CDC has asked doctors across the country to send them samples of blood and spinal fluid from anyone exhibiting symptoms. So far, no viral culprit has emerged, although polio has been eliminated as a possibility.
So are we dealing with a new polio?
Dr. John Bradley, director of infectious disease for Rady Children’s Hospital, doesn’t think so.
“I won’t say I’m not worried,” Bradley told the Light. “I’m just reassured. If it was going to be bad, I think we would know about it.”
From 2012 to date, there have been eight confirmed AFM cases in San Diego County — 96 in California during the same period — according to the California Department of Public Health.
“Each week that goes by without any more cases in San Diego, I’m reassured that it’s not likely to be an epidemic that people need to worry about — that it’s most likely a post-infectious condition,” said Bradley, who did not consult on any the San Diego cases himself.
Although its symptoms resembles polio, Bradley’s hunch is that AFM is caused by the body’s overreaction to fighting a virus rather than by a virus itself.
“One in every 5,000 to 10,000 kids who contracts chicken pox begins to stumble and fall and display signs of ataxia,” Bradley explained. “There is no virus there, but the immune system looks for specific proteins that the virus has and finds similar proteins in the body and begins attacking them.”
The recovery rate from this syndrome is similar to AFM’s, Bradley said: two-thirds, with the other third showing a gamut of permanent nerve damage.
“Doctors were aware of it, but the public generally wasn’t,” Bradley said, noting that the chicken pox vaccine has rendered this syndrome virtually nonexistent.
According to Bradley, the spikes in the CDC reports may simply represent better AFM reporting.
“Most doctors over the past few decades would not have thought to report a case they had to the CDC,” said, “so the rate that is quoted has been one that is associated with passive reporting. Once the word gets out that the CDC wants everyone to report their cases, then the number of cases go up.”
Still, with so little known about the condition, Bradley advises parental vigilance.
“Seek medical care right away if you or your child develop sudden weakness or loss of muscle tone in the arms or legs,” he said.Salk’s Two Cents
If the CDC does find an infectious agent to blame for AFM, how soon could a vaccine to fight it come to market? There’s no better place in the world to seek this answer than right here in La Jolla.
“With something so new and so unclear, it’s difficult to say,” said Jonathan Salk, the youngest son of Jonas Salk, developer of the polio vaccine.
“To make a vaccine involves so much science and also administration and also politics. There’s an enormous amount that goes into it, and that takes time.
“The polio vaccine came at a time (1955) that was so different, we could get the funds and do something on a large scale without having to step through all the hoops. We’ll never have that kind of experience again — of being able to put through a trial on that scale in that amount of time.”