Tuesday, 16 September 2014

What we know (and don't know) about a rare virus infecting kids across the US

A rare virus — enterovirus D68, also known as EV-D68 — is infecting children across the country and sending them to hospitals with severe respiratory infections and breathing problems. Though the virus doesn't appear to be deadly, the Centers for Disease Control and Prevention (CDC) are warning doctors and parents to be on the lookout.
"This is a very unusual situation," said Dr. Greg Storch, director of infectious diseases at St. Louis Children's Hospital in Missouri. "We don't fully know what to expect."
Here's what we know and what we don't know so far.

What we know

— Missouri and Illinois appear to be the first states affected by enterovirus D68. According to the CDC, hospital officials at Children's Mercy Hospital in Kansas City, Missouri and University of Chicago Medicine Comer Children's Hospital in Illinois notified the CDC in August about an increase in enterovirus cases that they were seeing. The CDC did further testing of specimens that were sent their way from the two hospitals and found that 19 of 22 from Kansas City and 11 of 14 from Chicago tested positive for EV-D68.
— In total, more than 100 children in seven states have tested positive for EV-D68 as of September 12, 2014. These include New York, Colorado, Illinois, Iowa, Kansas, Kentucky and Missouri.

— This infection shows no sign of slowing down. According to CDC, up to a dozen states may have potential cases and investigations are underway.

— All the cases involve young kids of both sexes, many of whom had a history of asthma or wheezing. Of the 19 confirmed cases from Kansas City, 10 were male, and their ages ranged from 6 weeks to 16 years, with a median of 4 years. Nearly 70 percent of patients had a previous history of asthma or wheezing. Of the Chicago group, nine of the 11 patients were female, and ages ranged from 20 months to 15 years with a median of 5 years. Nearly three-quarters had a history of asthma or wheezing.

— The kids stricken with EV-D68 had difficulty breathing and a good number of them experienced wheezing. They also had low blood-oxygen levels. Fevers were less common. In Kansas City, about five children (or a quarter) had fevers, while in Chicago, only two (or 18 percent) had fevers.

— According to the CDC, mild symptoms of EV-D68 can include fever, runny nose, sneezing, cough, and muscle aches. But again, the kids who got sick in Missouri and Illinois had symptoms that included difficulty breathing and wheezing. These patients were treated in pediatric intensive care units at the hospitals. Some needed help breathing with ventilation machines.


— No one has died from the virus this year, though the CDC says they can't be sure if the virus has ever been deadly since it's not a disease they usually track.

— There's not much you can do to treat it. There are no vaccines or antiviral treatments for EV-D68. The main kind of care is just supportive, so paying attention to symptoms and making sure people get proper fluids and help breathing, if necessary. Again, it doesn't appear to be deadly and the CDC's Dr. Anne Schuchat said she believes it typically runs its course in a week.

Dr. Pritish Tosh, an infectious diseases physician-researcher at the Mayo Clinic, added: "When dealing with respiratory illnesses in young people, they can be severe and result in hospitalizations and the requirement of intensive care. And it looks as through this strain of the virus is causing infections in children severe enough to get them admitted to the hospital."
Enteroviruses generally are very common. They usually turn up as "summer colds." There are more than 100 different strains, and they affect between 10 and 15 million people in the US per year. They can cause everything from encephalitis to viral meningitis.

Enteroviruses are typically spread through the fecal-oral pathway. That means pathogens in one person's feces infect another person by getting into their mouth, usually by touching the face and mouth with dirty hands.

This particular strain (EV-D68) spreads like the common cold through respiratory secretions, such as coughing, sneezing, or touching an infected surface. It was first identified in California in 1962. Compared to other strains of the enterovirus, it has been rare in the US. The CDC said that during 2009-2013, they got 79 reports of EV-D68 and it has been the cause of small clusters of sickness but never a widespread outbreak like the one that seems to have taken hold in the Midwest.
It's usually associated with respiratory illness — like a really intense cold — though the full spectrum of sickness that this strain can bring on is unclear. "We don't know as much about it as we do about some of the common respiratory viruses," said the CDC's  Dr. Schuchat.

EV-D68 is detected using molecular techniques at several labs across the US and it's not monitored nationally. According to the CDC, enterovirus infections including EV-D68, are not required to be reported. "But laboratory detections of enterovirus and parechovirus types are reported voluntarily to the National Enterovirus Surveillance System, which is managed by CDC. Participating laboratories are encouraged to report monthly summaries of virus type, specimen type, and collection date."
— The CDC says health care providers should be on the lookout for EV-D68 as a possible cause of serious and unexplained severe respiratory illness.
— Parents should only worry if their kids are having difficulty breathing. If your child is having trouble breathing, see a doctor.
— You can prevent spread through good hygiene. Wash your hands and make sure you have good cough etiquette.

What we don't know.

— We don't know why this strain has turned up in these geographic locations. Again, EV-D68 is thought to be rare so why it's turning up now in clusters across the Midwest, West, and South, and landing kids in hospitals, is unclear.
— Whether it has ever killed people. Since it's not a reportable disease, the CDC said it "does not know how many infections and deaths from EV-D68 occur each year in the United States."
— Public health officials are not sure about all the symptoms this strain of the virus can cause, since it's uncommon. That means EV-D68 may cause other types of illness beyond just respiratory complications, but we just don't know yet.
— Exactly who is most at risk. The CDC said, "In general, infants, children, and teenagers are most likely to get infected with enteroviruses and become ill. That's because they do not yet have immunity (protection) from previous exposures to these viruses. We believe this is also true for EV-D68." Kids with asthma seem to be more affected.

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— The total case count. The CDC says it's investigating potential cases but could not confirm that total number affected.

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