EHV-1 Hysteria

May 21, 2011 by · Leave a Comment 

Calm down horse people, all this EHV-1 hysteria is getting to me. As of today there are less than 40 horses that have contracted Equine Herpes Virus 1 from being exposed at a national cutting show in Odgen, Utah. Despite what certain news outlets are reporting it has not spread yet. Think about it there are over 7 million horses in the US, less than 40 have contracted the disease and less than 5 have died – 0.00057% of the population is definitely NOT an epidemic.

Yesterday I was a little disappointed in one of The Horse’s articles relating to the outbreak – EHV-1 Outbreak: Number of Confirmed Cases Rising. The title of this article and definitely the first line in the article really irritated me. Here is a respected health journal and they are playing to the hysteria that is building. Worse yet with the line, “It’s been nearly a week since the first indications of a neurologic equine herpesvirus-1 (EHV-1) outbreak began to surface, and the outbreak shows no signs of slowing down.” they certainly are continuing and even promoting that hysteria. I tweeted my disapproval with two tweets -

Oops Twitter conversation about horse health not loading.

Stephanie Church the Editor-in-Chief responded back to the tweets with a tweet of her own -

Oops Twitter conversation about horse health not loading

I agree with their mission and the responsibility they have placed on themselves which is why The Horse is an excellent source for articles on health for your horse (I have blog envy for sure). I said so and reiterated my displeasure with that specific title and first line of the article. Stephanie understood and followed up with this tweet -

oops Twitter conversation about horse health not loading

I am glad that Stephanie commented and listened to me explaining my displeasure and in the end seemed to be more conscious of what I was trying to say. I’d like to expand and clarify my position, first by saying that The Horse is by no means the problem here. They are still one of my most trusted sources for information about the outbreak. I also want to say that I am concerned about this outbreak but not to the point that I have seen some people and owners out here on the internet. On top of the hysteria, the misinformation is horrific. I can not believe with as much good information being repeated in many different reputable areas that there still is misinformation being given, even by veterinarians! And not only misinformation but information that may be detrimental to your horse’s health rather than helpful.

The Facts about this EHV-1 Outbreak

  • EHV-1 has been around a very long time and it is unknown at this time whether this outbreak is caused by a new strain.
  • EHV-1 causes respiratory disease, abortions, foal deaths and/or neurologic disease. If a horse obtains the neurologic form it is not a death sentence.
  • This outbreak has been limited to the horses that were exposed at the cutting show in Odgen, Utah and their stablemates. It has not spread to other horses.
  • Containment/Quarantine is the best defense against spread and it appears that at this time it has been contained by quarantining the horses that have been exposed.
  • Vaccination is ineffective against the neurologic form and controversial.

Reliable Sources for EHV-1 Information

A Few Words on Vaccination for EHV-1

First and foremost – the vaccine will NOT protect your horse against the neurological form of EHV-1. There were neurologic cases of EHV-1 in horses that were vaccinated every 3 to 4 months with an approved vaccine in the last outbreak. At this time there is not a labeled orĀ  approved product to protect your horse against the neurologic form. There is good reason for this – because there is not one that will protect against it!

There is promise though and break-throughs in research. The modified live vaccine shows some promise and did protect in one study of 5 horses, but still seemed ineffective in the outbreak a couple years ago. New advances in vaccine technology with recombinant DNA vaccines and Chimera type vaccines are also showing some promise but still are not available or ready to prove they are effective.

One of the biggest problems with the current vaccines, besides not being effective against the neurologic form, is the duration of so called protection. The vaccines currently available only protect for 3 months or so. (In some horses as little as a few weeks) So this means that if you really wanted to properly vaccinate you would need to vaccinate every 2-3 month, but it still will not prevent the disease and may only limit symptoms. It does prevent virus shedding which could possibly be of some benefit to limiting the exposure to other horses.

This is where my opinion comes in based on experience with the immune system and evidence from other species (cats and dogs). It is not advisable to be stimulating the immune system with a vaccine multiple times a year especially once every 60 days, unintended consequences may occur. In dogs and cats it has been proven that annual vaccination can and does cause immune system disorders such as allergies, auto-immune disorders and even cancer. Why would the horse be so different? And we are not talking about annual vaccination; here we are talking about giving a horse a vaccine every 2-3 months that’s 4 to 6 times a year. Talk about over vaccinating! It has not been proven in horses to have detrimental effects but it really has not been researched either. So in my opinion why would you risk your horses immune system to try and protect against a disease that it can not protect against? It is possible that the reason we see an increase in the neurologic form of the disease in vaccinated animals is because of over-vaccination. No research just an opinion based on other species experience with over vaccination.

In the end just remain calm horse owners. Be educated and informed. Pay attention to where the disease has occurred and realize that taking your horse to a show is a risk, but why do you have the horse in the first place?

About Dr Daniel Beatty
An Infopreneur with a Veterinary Medicine degree.