This summer a new outbreak, an unusual outbreak, from a virus called Enterovirus D68. This virus is causing some very serious trouble, and so we thought it would be helpful to explain what we know about it, and what to do.
What is a Virus?
As the name makes clear, all enteroviruses are types of virus.
Viruses are very strange sort of thing, they are packages of information wrapped in a coating that forces cells to make more copies of themselves. The information comes in the form of genetic material, either DNA or RNA and in every virus known these genes always code for instructions that force a host cell to activate the viral genes and then create a huge number of copies of the genes and new protective coats.
The protective coats of viruses are always made of a set of proteins that shield the virus from attack from an immune system, and contain properties that allow the virus to spread from person to person, find the right cell to infect, enter the cell, and deliver the viral genes to that cell to make copies.
What is an Enterovirus?
An Enterovirus refers to a very large number of viruses that cause a large number of viral illnesses in people. One subset of the Enterovirus family is the common cold virus, or Rhinovirus, but most Enteoviruses are described as belonging to a several subsets designated by letters, such as Enterovirus A, Enterovirus B, Enterovirus C, etc.
The prefix entero-, means having to do with the intestines, so the word enterovirus really minus, a gut or intestinal virus.
This makes sense since the typical Enterovirus causes a range of illnesses that include most of the stomach flus that happen in the summer, hand-foot-mouth disease, a high fever/stiff neck illness, and a simple bout of very high fever without any other symptoms.
One curious property of these, the typical Enterovirus illnesses, is that they only happen in the summer months, or close to them. This is a very important point and quite striking. The usual enterovirus is nowhere in the US in the winter. Almost no city in the US in the winter has the typical enteroviruses that cause stomach flu around in January. But come July, suddenly every city in the country is loaded with these viruses, in every neighborhood. No one knows why they disappear in cold weather and how they so suddenly erupt in the summer everywhere.
Another key property of Enteroviruses is that each subset or type has its own character, and some subtypes appear in clusters of cases over discrete periods of time. So there can be an outbreak of one particular Enterovirus subtype that creates a large number of cases over a few months, or even a few seasons, then disappears for many years, perhaps to never return, or to return in a few or many years hence.
We have seen years in which an Enterovirus creates a large number of cases of high fever, stiff neck, and very severe headache, for example. There have been stretches of 4-5 years of many such cases, followed by 10-20 years of far fewer.
So a particular subtype of Enterovirus can appear suddenly, then disappear as quickly, causing a stretch of time in which a striking illness occurs across the nation, followed by a stretch of time when such an illness disappears or becomes far less frequent.
What is Entervirus D68?
Remember that there are groups of Enteroviruses grouped by letters, like Enterovirus A and Enterovirus B? Well, this Enterovirus D68 is part of the Enterovirus D species of Enterovirus.
And it happens to be the 68th one in the group, hence Enterovirus D68. (There really are hundreds of all the different subtypes, or serotypes, of Enteroviruses, and five known Enterovirus D's.)
Enterovirus D68 is one of the subtypes of Enterovirus that come in clusters. There have been prior outbreaks of infection with Enterovirus D68, but none as large or concerning as the current one.
We do not know yet, but the hope is that with winter, this Enterovirus D68 will act like prior outbreaks, and like most Enteroviruses and stop causing illness during the winter.
Even more importantly, the hope is that this outburst of Enterovirus D68 is only this season, or if more, just a few years. This is a real hope, as noted such striking subtypes as Enterovirus D68 often drop off over time.
What Illnesses Does Enterovirus D68 Cause?
The Enterovirus D68 is different than most classical Enteroviruses in that it infects the lungs more than the guts, so it causes more breathing problems than vomiting and diarrhea. But sadly, it also seems to attack the nervous system, although not as commonly as the lungs.
Here are the key symptoms seen. That means, if one gets an infection with Enterovirus D68, it causes these symptoms most commonly. It does not mean if you have these symptoms you have Enterovirus D68:
- Nose symptoms: runny nose, sore nose, sneezing, headache
- Throat symptoms: sore throat, hoarseness
- Lung symptoms: cough, wheeze, real trouble breathing
- Nerve and Muscle symptoms: less commonly than the above- weakness, inability to move limbs (paralysis). These symptoms are not yet proven to be caused by Enterovirus D68, in one outbreak in Colorado, nine children developed loss of movement function (paralysis) and have Enterovirus D68 infection, but none of the virus was found in their cerebrospinal fluid, so we need further study to know if this symptom is indeed possible with this infection.
- Some gut symptoms: mildly loose stools, stomach aches
- Skin symptoms: various rashes
What to DO!
The answer to what to do is the same for Enterovirus D68 as it is for every virus: if symptoms are mild, just keep your child comfortable. If symptoms are worrisome, call us for help, and we will arrange for care to reduce the danger the infection presents.
Why do all viral illnesses have the same advice? Because for nearly all viral infections, there is no drug or treatment that kills the virus or heals its inflammations.
When to Worry
Even if one is infected with Enterovirus D68, if the only symptom is a mild runny nose, there is no cause for any concern.
And of course, even if the virus is not Enterovirus D68, if someone is struggling to breathe, you should call for help right away.
So, for Enterovirus D68, we are less concerned and there is very little to do, if symptoms are limited to this list:
- runny nose, sore throat, cough, mild stomach aches, mild rash, and/or slightly soft stools; but, breathing fine when not coughing.
If any of the following symptoms appear, call for help right away:
- Severe difficulty breathing, meaning your child has to work very hard to get air in and out of his or her chest
- Muscle weakness beyond the mild tiredness of being ill. Your child seems very weak, and of course, if they cannot move an arm or leg
If we see your child and they have the mild symptoms, the treatment will be to keep your child comfortable at home without any specific testing. As long as the symptoms remain mild, it makes no difference what the virus is, the treatments and care remain the same.
If we speak to you or see your child and they have the more severe troubles of struggling to breathe or having significant changes in muscle strength, then the treatment is quite different. In this situation we would arrange for evaluation and care at the hospital. Tests for Enterovirus D68 and other viruses and germs would be done, and specific therapies to help a person breathe and to help a person who is getting weak, would all be started.
- The Enteroviruses are a very common and large number of viruses that typically cause the summer stomach flu, hand-foot-mouth disease, and other mild summertime illnesses.
- Now and then subtypes of the Enterovirus family show up in outburts that bring unusual and severe disease. This is what is happening with Enterovirus D68, a strain causing quite severe and unusual breathing problems.
- As with nearly every virus, there are no drugs to cure or heal the infection.
- When it comes to knowing when to worry, when your child gets a cold or respiratory infection, it does not matter so much what the name of the virus is, even if it is Enterovirus D68. What does matter is how sick your child is. If the cold or respiratory infection is mild, no worries. If the infection is causing your child to struggle to breathe or become severely weak, then it is time to worry, to call us for help. Again, this is true no matter the name of the infecting germ.
- Lastly, this outbreak of Enterovirus D68, which has caused so many cases of severe trouble breathing, will hopefully go away. Time will tell. Enteroviral outbreaks of severe illness typically appear mainly in the summer for several years, then seem to stop happening. Our hope is that this round of Enterovirus D68 is limited solely to the summer of 2014, goes away this winter, and does not return. We will watch to see how it goes.
To your health!
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