Enterovirus D68: Sweeping across the US

The respiratory virus known as Enterovirus D68 (EVD68) has been sweeping the country this summer, primarily infecting children. So far 691 people in 46 states have been infected. Luckily, enterovirus is typically a summer virus, and it’s season shall soon come to an end.

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 Children with Asthma may have Worse Outcomes with EVD68

While the signs and symptoms of EVD68 generally mirror that of other  respiratory viruses and can include fever, runny nose, sneezing, cough, and body and muscle aches. In some children wheezing and difficulty breathing can develop.  The most deadly form of the virus seems to be more widespread in the Midwest. At the peak of the Kansas City-area outbreak their 354-bed hospital was filled, and Children’s Mercy had 100 patients in their pediatric intensive care unit (PICU), three times more than normal for this time of year. Patients usually end up in the PICU due to severe bronchospasms, and often many children affected by the virus suffer from asthma or have had episodes of wheezing in the past. This video describes EVD68 in more depth.

CDC Launches New, Faster EVD68 Testing

CDC’s new lab test is a “real-time” reverse transcription polymerase chain reaction, or rRT-PCR that identifies all strains of EV-D68 present this summer and fall. The new test has fewer and quicker steps than the test that CDC and some states were using for the EV-D68 epidemic.

Since the outbreak of EV-D68 began in August, CDC has tested 1163 specimens submitted by hospitals and from 45 states.  Of the specimens tested by the CDC lab from August 1 to October 10, about half have tested positive for EV-D68. About one third have tested positive for a rhinovirus or an enterovirus other than EV-D68. The new lab test will allow us to process the approximately one-thousand remaining specimens at a much faster rate.

Ultimately, faster testing will help to better show the trends of this outbreak since August and to monitor changes that are occurring now. CDC expects to complete testing of the remaining specimens that were received since mid-September within about seven to 10 days; going from testing about 40 specimens per day to testing up to 180 per day.  This will allow us to then test and report results for new specimens within a few days of receiving them.

EVD68 and Paralysis

The virus has been recently implicated in 10 cases of apparent paralysis in children in Colorado who were hospitalized between August 9 and September 28th. The virus seems to be causing proximal weakness, affecting primarily the shoulder, triceps, biceps and hips, with some having additional weakness in the neck and facial muscles. MRI abnormalities have been noted in the spinal gray matter of these children.

In a report in Morbidity and Mortality Weekly Report, the characteristics of this paralytic outbreak were detailed:

On September 12, 2014, CDC was notified by the Colorado Department of Public Health and Environment of a cluster of nine children evaluated at Children’s Hospital Colorado with acute neurologic illness characterized by extremity weakness, cranial nerve dysfunction (e.g., diplopia, facial droop, dysphagia, or dysarthria), or both. Neurologic illness onsets occurred during August 8–September 15, 2014. The median age of the children was 8 years (range = 1–18 years). Other than neck, back, or extremity pain in some patients, all had normal sensation. All had a preceding febrile illness, most with upper respiratory symptoms, occurring 3–16 days (median = 7 days) before onset of neurologic illness. Seven of eight patients with magnetic resonance imaging of the spinal cord had nonenhancing lesions of the gray matter of the spinal cord spanning multiple levels, and seven of nine with magnetic resonance imaging of the brain had nonenhancing brainstem lesions (most commonly the dorsal pons). Two of five with magnetic resonance imaging of the lumbosacral region had gadolinium enhancement of the ventral nerve roots of the cauda equina. Eight children were up to date on polio vaccination. Eight have not yet fully recovered neurologically.

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It is important to note, however, that EVD68 has not yet been confirmed as the cause of this paralysis, with the CDC calling the outbreak to be of ‘undetermined etiology’. Enterovirus was found in the nasal passages of 6 of 8 patients who were tested. Of these six, four were found to have EV68. “We don’t know, at this point, if there is any association between the enterovirus EV-D68 that’s circulating and the paralytic conditions some of the children in Colorado are experiencing,” CDC spokesman Tom Skinner said. Dr. Mary Ann Jackson of  Mercy Children’s Hospital explained, “the virus is only going to be in the nose [the site of the test] for a period of time, and the timeframe between onset and presentation can be a few days to a few weeks. The virus could be gone by the time the limb weakness occurs. So far, there is still nothing to prove that the neurological symptoms have to do with EV-D68. But EV-D68 is the focus of the investigation.”

The CDC is asking, however, for physicians to be alert and to report any patients who are 21 or younger and experience acute onset of focal limb weakness occurring on or after August 1, 2014 AND an MRI showing a spinal cord lesion largely restricted to gray matter. This CNN report provides further information.

Currently the CDC recommends taking basic precautions to prevent infection with EVD68.

EV68-infographic (1)

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