Genomic data further indicate association between enterovirus D68, neurological illness
Extensive genomic data recently published in The Lancet Infectious Diseases supported the association between enterovirus D68 and acute flaccid myelitis.
“In 2014, in the US, a nationwide outbreak of enterovirus D68 occurred in association with severe respiratory illness, with more than 1,150 confirmed cases,” study researcher Alexander L. Greninger, MD, of the University of California, San Francisco, and colleagues wrote. “This enterovirus D68 outbreak coincided with an apparent increase in incidence of reported cases of acute flaccid paralysis, including a temporally associated cluster in Colorado.”
To investigate the association between enterovirus D68 (EV-D68) and acute flaccid myelitis, researchers conducted metagenomics next-generation sequencing, viral genome recovery and enterovirus D69 phylogenetic analysis among 48 patients who presented with acute flaccid myelitis between Nov. 24, 2013 and Oct. 11, 2014.
Twenty-five study participants had acute flaccid myelitis, 16 had aseptic meningitis or encephalitis and tested positive for enterovirus, five had upper respiratory illness associated with EV-D68 and two had enterovirus-associated encephalitis.
Forty-eight percent of nasopharyngeal or oropharyngeal samples from patients with acute flaccid myelitis tested positive for EV-D68 via screening and sequencing with two different reverse transcriptase polymerase chain reaction (RT-PCR) assays.
To further investigate potential neuroinvasive infections, researchers analyzed enterovirus-positive cerebrospinal fluid from 16 patients who presented with aseptic meningitis or encephalitis. None of the cerebrospinal fluid samples were positive for EV-D68 according to RT-PCR screening and confirmatory screening results.
Phylogenetic analysis indicated that all of the 11 EV-D68 viruses associated with acute flaccid myelitis belonged to a clade B1 that emerged in 2010.
“Our data strengthen the putative association between enterovirus D68 respiratory infection and acute flaccid myelitis and suggest that the detection of enterovirus D68 in respiratory secretions from patients with acute flaccid myelitis is unlikely to be incidental,” Greninger and colleagues wrote. “Since all patients with acute flaccid myelitis in the present study continue to have residual limb weakness or other neurological deficits, further investigation of the neuropathogenic potential of enterovirus D68, especially clade B1 strains, is needed.” – by Amanda Oldt
Disclosure: Greninger reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.