A virus that can cripple children appears to be on the rise again. US wastewater data show an increase in enterovirus D68, which can cause a rare, polio-like condition known as acute flaccid myelitis, or AFM. AFM outbreaks have followed the rise of EV-D68 in recent years, although recorded cases so far remain low in 2024.
In general, EV-D68 causes more than a minor respiratory infection. But a decade ago, scientists began to notice that some children infected with the virus ended up developing AFM. The main symptoms of AFM are unexpected physical weakness, while some will also develop facial weakness, slurred speech, and pain in the legs and back. In severe cases, people can have life-threatening paralysis that affects breathing, and some may be permanently disabled.
EV-D68 is related to the poliovirus, which has long been known to cause a similar paralytic condition in about 0.1% of victims. And research has found that certain strains of EV-D68 have mutated to resemble polio and potentially cause AFM. Although there are other viral causes of AFM, scientists have firmly tied the arrival of these new strains to an unprecedented outbreak of AFM in the US that dates back to at least 2012. Although hundreds of children in the US have suffered from AFM since then, it is still a very rare complication of any EV-D68 infection. Now it looks like the EV-D68 and the possibly returning AFM will stir up trouble.
According to data collected by WastewaterSCAN, a national monitoring program that analyzes wastewater samples conducted by researchers from Stanford and Emory University, the presence of EV-D68 in the country has increased significantly since the beginning of August. Since the outbreak of the covid-19 pandemic, wastewater data has been reliably used to provide early warning of infectious disease outbreaks. Historically, EV-D68 outbreaks have peaked in the US during the summer and fall.
“We’re finding EV-D68 nucleic acids in wastewater all over the country now, and the levels are increasing,” Alexandria Boehm, WastewaterSCAN program director and professor of civil and environmental engineering at Stanford University, told NBC News on Tuesday.
There is a curious wrinkle that has emerged in recent years. Since 2012, large outbreaks of AFM have appeared immediately following large outbreaks of EV-D68, which appear around the clock every two years in the US. But the covid-19 pandemic disrupted the flow of many other infectious diseases, EV-D68 included, thank you especially in increasing social distancing in those early years. In the summer of 2022, EV-D68 appeared again, but it was followed by a silent increase of AFM, with only 47 cases recorded by the Centers for Disease Control and Prevention that year (in comparison, the outbreak of previous years was seen between 120 cases and 240 for AFM). And so far, the incidence of AFM has remained low this year as well, with only 13 cases so far.
It’s possible that the EV-D68 has also changed to be less likely to cause AFM, but it’s probably too early to know for sure. In any case, experts will be closely monitoring the situation and continue to study the virus. Scientists are also working to further contain the threat posed by EV-D68. In June 2024, the National Institutes of Health announced that it is funding a clinical trial testing a lab-antibody against EV-D68—aimed at eradicating the virus before it causes AFM.
It will likely take years for this treatment to reach the public, even if this and other trials go well. But should AFM become a common threat again, having this potential preventative treatment could be helpful for many families in the future.
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