A paralytic illness that’s struck down hundreds of children across the U.S. in recent years has baffled medical experts looking for a cause. Case of the polio-like disease, known as acute flaccid myelitis or AFM, has spiked every two years since it was first recognized in 2012. Now, medical experts are pointing to a common pathogen as a possible culprit.
AFM is a neurological condition that mostly affects young children, with nearly 600 cases confirmed across the U.S. since 2014. Symptoms usually begin like a typical cold, but can steadily progress into severe neurological damage. Patients may experience reduced reflex movements, limb weakness, and paralysis. There’s currently no specific way to prevent AFM.
Researchers now believe that a virus known as enterovirus D68 (EV-D68) may play a key role in the development of AFM. EV-D68, first identified back in the 1960s, is a relatively common pathogen that has been long associated with mild respiratory problems. It is one of more than 100 different enteroviruses that have been found to affect humans.
Enteroviruses have been suspected in AFM, partly because of its similarity to polio, another type of enterovirus. Many of those diagnosed with AFM have reported experiencing mild respiratory problems in the early stages of the illness and there has been an overlap in outbreak locations between AFM and EV-D68. In 2017, researchers found that the virus was capable of causing paralysis in mice.
Researchers studying the issue have uncovered signs of EV-D68 in the spinal fluid of patients affected by AFM. Researchers from the University of California, San Francisco used a library of just under half a million virus proteins to see if antibodies that recognize the enterovirus were present in the patients’ spinal fluid. They found that more than two-thirds of the samples from patients with AFM had antibodies matching proteins belonging to EV-D68’s virus family and genus, versus just 7 percent of the controls.