There’s no need to panic about enterovirus

The news these days is awash in viruses. The tragedy of the Ebola outbreak has seized headlines, as it should, but there’s another virus lurking beneath the fold, one that has some parents and schools worried. This mysterious enterovirus has been linked to severe respiratory diseases and even deaths in kids around the United States.

From mid-August to October 17, the virus, called EV-D68, has been found in 825 people, almost all children, the Centers for Disease Control and Prevention reports. And the virus was found in seven patients who died (but it’s not clear whether the virus caused those deaths).

So of all the potential terrors out there — Ebola, razors in Halloween candy — just how much headspace should parents devote to worrying about this particular enterovirus? The answer seems to be not much (and the same goes for Ebola and deadly Halloween candy), but it’s still worth knowing a little about where this virus came from and what we know about it.

What is this virus?

Enteroviruses are extremely common, often causing mild symptoms or no symptoms at all. And despite EV-D68’s reputation as a scary new threat, this enterovirus has been around for years. In fact, it was first isolated in 1962 from four kids in California. Since then, scientists have seen EV-D68 sporadically pop up in small clusters. Over the past two decades, distinct forms of the virus have been circulating all over the world, molecular microbiologist Rafal Tokarz of Columbia University and colleagues reported in the Journal of General Virology in 2012. Historically, EV-D68 has been linked to mild symptoms, such as a runny nose, sneezing, coughing and fever.

What’s different this time?

The scope of the outbreak is much bigger, says virologist Steve Oberste of the CDC in Atlanta. “We’ve never seen anything quite like this,” he says. A surveillance survey of enterovirus infections that were reported to the CDC between 1970 to 2005 turned up just26 cases of EV-D68, he says. Compare those piddly numbers to this year’s caseload, which so far includes 825 people in 46 states and the District of Columbia.

The virus also seems to be linked with more severe symptoms. Previous cases of EV-D68 were associated with mild symptoms. This year’s batch seems to be causing more trouble, particularly in kids who already had breathing problems, such as those with asthma, says Tokarz.

The virus has also been found in seven people who died, but it’s important to keep in mind that doctors have no idea whether the virus actually caused those deaths. That means that headlines that say things like “Michigan toddler dies of enterovirus D68” are getting way ahead of themselves. That ambiguity raises some other sticky issues: Figuring out how many kids actually have the virus and how dangerous it can be is actually quite tricky, Tokarz says.

Is this year’s virus actually different, or are we just better at finding it?

In the past, people often found EV-D68 when they were looking for other viruses, Tokarz says. When he and his colleagues went looking for influenza in New York City a few years ago, the scientists stumbled across a small cluster of EV-D68 cases. It could be that the virus has been lurking in all of our noses, but no one thought to look for it seriously until now.

It’s also possible that this latest outbreak’s version of EV-D68 really is having an outsized effect, perhaps because it has mutated to spread more easily between people or mutated to cause more severe symptoms. CDC scientists have publicly released one complete genome sequence from EV-D68, and several more partial sequences. At first glance, no obvious mutations jump out as being particularly important, Oberste says, but more detailed analyses may reveal relevant changes.

The virus may be a little bit more menacing than in years past, and we may be looking for it harder. “My guess is that it’s a combination of both,” Tokarz says.

When will it end?

Like other enteroviruses, EV-D68 will probably peter out as the weather gets colder. Already CDC is seeing fewer cases in some states. (A newly released faster test to detect the virus might make numbers temporarily seem higher than they are as labs work through backlogged samples, but most of those cases will be weeks or months old.)

Why does the virus hit children?

Most adults have suffered through all sorts of gross enteroviruses and rhinoviruses, which can cause the common cold. As a result, our immune systems may be able to neutralize EV-D68 because of its similarity to other viruses we may have had. Kids with naïve immune systems have no such luck. That’s the same reason that hand, foot and mouth disease is usually a childhood affliction.

Are there treatments?

No. Aside from polio (another enterovirus), there are no vaccines for EV-D68. Scientists are working on developing drugs that counter similar infections, but none are available now, says Oberste.

Your best bet is to avoid the virus in the first place, and we already know how to do that: Wash hands, cover coughs and don’t let your kids bob for apples right after a sick kid. If a child shows signs of respiratory illness, keep her home from school. In any event, it’s definitely not time to panic, Tokarz says. “I have two small kids and I’m not afraid to send them to school.”

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