MAR 31, 2015 8:53 AM PDT

Unexplained Childhood Paralysis Linked to Enterovirus D68

WRITTEN BY: Judy O'Rourke
A research team led by scientists from the University of California, San Francisco (UCSF) has found the genetic signature of enterovirus D68 (EV-D68) in half of the California and Colorado children diagnosed with acute flaccid myelitis - sudden, unexplained muscle weakness and paralysis - between 2012 and 2014, with most cases occurring during a nationwide outbreak of severe respiratory illness from EV-D68 last fall.

The finding strengthens the association between EV-D68 infection and acute flaccid myelitis, which developed in only a small fraction of those who got sick.
A 3-D image of enterovirus D68 (center) reconstructed from cryo-electron micrographs (background).
The scientists could not find any other pathogen capable of causing these symptoms, even after checking the cerebrospinal fluid for every known infectious agent.

Researchers analyzed the genetic sequences of EV-D68 in children with acute flaccid myelitis and discovered that they all corresponded to a new strain of the virus, designated strain B1, which emerged about four years ago and had mutations similar to those found in poliovirus and another closely related nerve-damaging virus, EV-D70. The B1 strain was the predominant circulating strain detected during the 2014 EV-D68 respiratory outbreak, and the researchers found it both in respiratory secretions and - for the first time - in a blood sample from one child as his acute paralytic illness was worsening.

The study also included a pair of siblings, both of whom were infected with genetically identical EV-D68 virus, yet only one of whom developed acute flaccid myelitis.

"This suggests that it's not only the virus, but also patients' individual biology that determines what disease they may present with," says Charles Chiu, MD, PhD, associate professor of laboratory medicine and director, UCSF-Abbott Viral Diagnostics and Discovery Center. "Given that none of the children have fully recovered, we urgently need to continue investigating this new strain of EV-D68 and its potential to cause acute flaccid myelitis."

Among the 25 patients with acute flaccid myelitis in the study, 16 were from California and nine were from Colorado. Eleven were part of geographic clusters of children in Los Angeles and in Aurora, Colorado, who became symptomatic at the same time, and EV-D68 was detected in seven of these patients.

Although the researchers found EV-D68 in the children's respiratory secretions and in the blood from one case, they did not find it in cerebrospinal fluid. The researchers said this may not be surprising given that other nerve-damaging viruses, like polio, are also extremely difficult to detect in cerebrospinal fluid.

Eighty percent of the children reported having an upper respiratory illness about six days, on average, before their acute flaccid myelitis symptoms began. Slightly more reported having a fever, including all of the cases from the clusters in California and Colorado.

Samples were collected more than a week after the children began showing symptoms of an upper respiratory infection, and this likely made it much harder to find EV-D68. There may also be other reasons to explain why the virus was not found in cerebrospinal fluid in children with neurological symptoms.

"The lack of detectable virus in CSF could also mean that the neurological symptoms are coming from an aberrant immune response to recent EV-D68 infection and not because the virus is directly invading neurons," says Chiu, senior author on the paper published March 30 in The Lancet Infectious Diseases.

[Source: UCSF]
About the Author
  • Judy O'Rourke worked as a newspaper reporter before becoming chief editor of Clinical Lab Products magazine. As a freelance writer today, she is interested in finding the story behind the latest developments in medicine and science, and in learning what lies ahead.
You May Also Like
MAR 23, 2021
Coronavirus
A Mother-to-Fetus COVID-19 Transmission Has Devastating Consequences
MAR 23, 2021
A Mother-to-Fetus COVID-19 Transmission Has Devastating Consequences
A pregnant woman infected with the pandemic virus SARS-CoV-2 passed the virus on to her unborn child through the placent ...
MAR 24, 2021
Cancer
What toxic chemicals are lurking in your couch?
MAR 24, 2021
What toxic chemicals are lurking in your couch?
New research published in the journal Environment International suggests a weekend trip to the nearest furniture st ...
MAR 24, 2021
Cardiology
Supplement Can Prevent Strokes in Patients with Rare Disease
MAR 24, 2021
Supplement Can Prevent Strokes in Patients with Rare Disease
Scientists have found that it may be possible for people with a rare genetic disorder to prevent fatal strokes by taking ...
MAR 28, 2021
Genetics & Genomics
Fish Oil Benefits May Depend on a Person's Genetics
MAR 28, 2021
Fish Oil Benefits May Depend on a Person's Genetics
The benefits of fish oil have been debated for years. New research can explain why it's been difficult to reach a solid ...
MAR 30, 2021
Drug Discovery & Development
Common Alzheimer's Drugs Reduce Mortality Rate and Cognitive Decline
MAR 30, 2021
Common Alzheimer's Drugs Reduce Mortality Rate and Cognitive Decline
Researchers from the Karolinska Institute and Umea University in Sweden have found that a commonly recommended group of ...
APR 19, 2021
Microbiology
Gas-Generating Microbes Highlight the Diet - Microbiome Link
APR 19, 2021
Gas-Generating Microbes Highlight the Diet - Microbiome Link
Researchers are learning more about how different species of bacteria in the human gut microbiome play a role in metabol ...
Loading Comments...