Top U.S. disease experts shared commentary in MBio on Tuesday that acute flaccid myelitis (AFM), the rare illness that strikes mostly young children and causes limb weakness or paralysis, may be caused by a "hit and run" virus and could become more prolific — but research acceleration is needed to know more.
Why it matters: Researchers have been seeking the elusive cause of the illness — which rarely leaves traces of any causative agent in the spinal fluid as expected — since AFM popped onto the national radar as a major outbreak in 2014 and reached a record number in 2018.
What's new: "Circumstantial evidence suggests a strong relationship between [enterovirus D68] and AFM," Anthony Fauci, National Institute of Allergy and Infectious Diseases director and co-author of the commentary, told Axios.
- The Centers for Disease Control and Prevention published new figures last week on EV-D68 showing a strong increase — of 14%— in detected infections in hospitalized patients in 2018, compared with the prior year of 1%. Detections of EV-D68 peaked in September — the same month that AFM peaked last year.
- There was a record number of illnesses in 2018 with 228 confirmed cases in 41 U.S. states, and 4 confirmed cases in 4 states this year so far. Most of the children diagnosed had cold-like illnesses with low fevers that got better, but experienced sudden-onset of muscle weakness or paralysis 3 to 10 days later.
But, but, but: Not every year with an uptick in AFM — which so far has been cyclical
with an increase every 2 years — has also correlated with EV-D68, although it's been a prime suspect. Among others, enterovirus A71 has also been a suspect.
- The authors suggest there could be a "hit-and-run infection" by EV-D68 or another virus, which may have run its course but triggered an immune response or caused other effects. Then it's the paralyzing event that demands testing of blood, stool or spinal fluid, at a point when the virus is out of the patient's system.
- Another possibility is we could be "entering some kind of new epidemic era" of viral mutations, they write.
What's next: Research is continuing into both the causes and treatments, for which the CDC has interim guidelines.
The bottom line: While there's "significant suggestion" that EV-D68 plays a role in AFM, it's "very frustrating when you don't know the etiology of the infection," Fauci says. In the commentary, the scientists wrote...
"Watching healthy children become permanently paralyzed virtually overnight by a seemingly random, lightning-strike disease is as heartbreaking today as it was in the polio era."
"The trajectory of AFM over the past 5 years suggests that the problem is getting worse, and so it is critical that we galvanize our efforts to learn more about, and respond adequately to, this ubiquitous, often crippling, continually reemerging group of viruses."