Enterovirus infection and acute flaccid myelitis

Recent outbreaks of limb paralysis similar to poliomyelitis, termed acute flaccid myelitis (AFM), have prompted intense investigation into potential etiology. Peaks of AFM were seen in the United States in 2012, 2014, 2016 and 2018, coincident with peaks in enterovirus transmission, particularly EV-D68. Similar peaks of AFM and EV-D68 circulation were reported in other parts of the world. The causal relationship between EV-D68 is still not widely accepted as it is for poliovirus and EV-A71, the latter of which is endemic in the US. Recent in vitro and mouse model data as well as enhanced-sensitivity diagnostic assays have provided further evidence linking the causal relationship between EV-D68 and AFM. In addition, an outbreak of EV-A71-associated AFM was recently described, highlighting the possibility of an additional emerging non-polio enterovirus of public health concern. As AFM is a devastating disease with poor prognosis in many children, particularly those with EV-D68, recent studies call for increased surveillance, pursuit of novel therapeutics and strategies to prevent transmission before the next outbreak.