The rapid, nationwide spread of the enterovirus 68 respiratory infection is unlike any previous outbreak of the disease public health officials have seen.
As of this week, the Centers for Disease Control and Prevention have confirmed nearly 500 cases of the infection, including four in patients who died, although it’s uncertain what role the virus played in their deaths. Experts say the true number of cases is likely much higher, since only a fraction of patients suspected of having the infection have been tested, and the infection is usually neither fatal nor severe.
Most of the patients seriously affected are children. Experts say thatparents should be on the lookout for children with difficulty breathing, chest pain, wheezing or blue lips. Those are signs that the child requires immediate medical care. Children with asthma and other chronic lung conditions are particularly vulnerable.
Q.
Until recently a lot of people had never heard of enterovirus 68. Is this outbreak — or the scope of it — unusual?
A.
I think the most surprising aspect of it is how severe it is, particularly the symptoms in kids. Because that hasn’t really been seen before. As far as the extent of it, in the past 10 years, there have been reports by our group as well as several around the world that the virus has been increasing in incidence. There have been clusters in Southeast Asia, in Europe, in Africa and in North America. It’s been increasing in the past decade.
Q.
What is different about the symptoms seen in this outbreak compared to previous clusters?
A.
In most cases it manifests itself as a cold or maybe a mild case of the flu, and it probably got diagnosed as such. I believe in a lot of cases it’s still no different than a severe cold or the flu, even during this outbreak. But in certain individuals the symptoms are more severe, and that hasn’t been seen before. What’s different now is that kids are going to the I.C.U. But the fact is that we don’t know a lot about this virus. Until the last 10 years or so it was very rare.
Q.
Why is this outbreak so different than others? Is the virus evolving?
A.
Absolutely. It is evolving. A hypothesis of mine is that the strain that’s circulating now probably is a novel variant. It may have mutated into something that’s more easily transmissible and more pathogenic. The virus is mutating, and there are a lot of different variants circulating around the globe.
We don’t know much about this particular strain because that data to my knowledge hasn’t been released yet by the Centers for
Disease Control and Prevention. But enteroviruses do change over time fairly rapidly. If you look at the strains that were circulating in the past, the strains from 10, 15 or 20 years ago, they’re very different genetically.
Disease Control and Prevention. But enteroviruses do change over time fairly rapidly. If you look at the strains that were circulating in the past, the strains from 10, 15 or 20 years ago, they’re very different genetically.
Q.
Why is this outbreak so much more widespread than previous ones?
A.I would guess that the strains that are circulating now are basically more transmissible. They can be spread more easily from person to person – maybe more infectious. That’s something we won’t know until we can compare the strains circulating now to earlier strains. So we won’t know that for a while.
Q.
Some studies suggest that in the past, enterovirus 68 may have been commonly overlooked or mistaken for similar infections, like the common cold. Is that true?
A.
It definitely was under-reported. It’s likely there had been more cases last year and many of them were missed because enterovirus was not something one would immediately think of since the virus was so rare.
This is really the first time there’s been such a large outbreak with severe symptoms. But in the past, there have been clusters in the United States. We discovered a cluster in New York City in 2009. There were clusters documented across the United States in 2009 and 2010. So there have certainly been clusters of this virus in the past but what is different now is the scale and the symptoms.
Q.
The outbreak this year is largely affecting children. Is that typical of enterovirus?
A.
In most cases, yes. It’s always been associated predominantly with children – probably because they show more symptoms. But it has been reported in adults as well. There have been cases in adults documented here in the United States and in Asia as well. It affects adults as well, but with less severe symptoms.
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