An Endurance Vet's Take on EHV-1

Tuesday May 24 2011

With the concern about EHV-1 still high, I thought this post was worth passing on.

Dr Susan Garlinghouse is the head veterinarian for the Montana de Oro endurance ride coming up June 4 in southern California. She's described as "always very sensible and not prone to panic."

From Susan:
There have been a lot of questions about potentially cancelling or rescheduling upcoming rides given the recent outbreak of EHV-1 in various western states, including California. The decision to do so remains with the individual ride management based on the risk in their area. Since I’m head vetting the upcoming Montana de Oro June 4th in Los Osos, California, which is going forward as planned, I wanted to put forward a few thoughts and suggestions for those entered. Management disclaimer: although I am a member of the AERC vet committee, and this post is in line with the committee’s current thoughts, please don’t take this post as being an official publication of that committee---these are just coming from me as a head vet, so take it as you will.

1) It just makes sense to keep yourself appraised as to the current progress of this outbreak in your area. Daily updates on the outbreak in California can be found at the California Dept. of Food and Agriculture here: http://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html

This includes specific information about numbers of horses exposed, displaying
clinical symptoms, numbers of horses under treatment or having died or been euthanized. There are also multiple links for information available on the AERC website at www.aerc.org . Please note that with one exception, all of the horses testing positive (currently seventeen of them throughout the state) competed at either the cutting event in Ogden, Utah, or at the event in Bakersfield, CA. The one exception is a mare that has tested negative to the mutant strain of EHV-1, but is displaying similar neurologic symptoms---she seems to be a coincidentally occurring case of the more common strain of EHV-1, but she too is under quarantine and treatment at UC Davis. I suggest every horse owner planning on competition in the near future check this website daily for updates on the progress of this outbreak.

2) Although this disease is definitely highly contagious, the virus doesn’t live for very long time in the environment (generally about a week and only under ideal circumstances up to a month) and is susceptible to virtually any kind of disinfectant---dilute bleach, betadine solution or scrub, chlorhex, hand sanitizers, etc. There have been anecdotal reports of certain service providers such as shoers and equine ‘dentists’ proclaiming they are cancelling all appointments for the next three weeks and throwing away all their equipment. If this is the case, I would like to volunteer my services to pick up and disinfect all those discarded tools, which you will then be seeing for sale on eBay within a day or so after a ten-minute soak in a bucket of diluted bleach.

The take-home message here is let’s use some common sense in biosecurity. The few properties under quarantine in So Cal aren’t going to be allowing non-essential providers onto the property to perform services, anyway, so it’s highly unlikely contagion is going to be transported to their other clients. If you feel strongly about it, ask your shoer if he would mind if you sprayed some alcohol or dilute bleach over their equipment before starting on your horse, ask him to wash his hands and to please not poke any of his tools up your horse’s nose. Keep in mind that at the moment, there are only six properties throughout the entire state with potentially exposed horses, and all of those are already under quarantine (most of them in the northern end of the state), so it’s really unlikely your shoer is going to be a source of EHV-1 coming onto your place in So Cal. Also keep in mind that all but one of the positive horses were those competing at the two cutting events---there have not been any cases of second ary spread of the virus. We are also already past the 2-10 day incubation period typical for EHV, meaning that in all likelihood, horses exposed to the disease that are going to show symptoms already have.

3) If you are entered for this ride, and you board at a quarantined facility, clearly your plans are going to have to change. If you board at a facility where cutting horses also board that competed either at the Ogden or Bakersfield event, then you should re-consider coming to the ride. At the very least, monitor any potentially exposed horses closely by taking a rectal temp twice a day---EHV first shows up as an elevated temp of 102 or higher, so if your horse is running a fever, don’t come---not only is he a potential risk to other horses, he’s too sick to be competing in endurance, anyway. Stay home and call your vet.

4) If you plan on coming to the ride (and I hope you do), then take a few additional measures en route. Don’t stop at any rest stops where other horses might have been recently, like horse motels, fairgrounds, show venues, etc. We all know plenty of places to unload and stretch our legs along the way that are unlikely to have recently housed cutting horses traveling to or from Ogden or Bakersfield, so use those out-of-the-way places, not the more public places. At this point, it’s unlikely a significant amount (if any) virus is still lurking in the environment outside of quarantined facilities, but it doesn’t hurt to be a bit more careful. Don’t use public water sources at horse stops, don’t use public corrals or tie rails, don’t borrow buckets or tack. Use some common sense---there are plenty of contagious diseases floating around out there totally aside from EHV-1, so just as you would (hopefully) take some additional personal hygiene measures when out in public yourself, take the same precautions when traveling to any event with your horses.

5) Finally, be aware that as of this moment, I do not plan to take any unusual biosecurity measures at this upcoming ride, other than possibly dunking my hands in a bucket of disinfectant between horses at checks and checking rectal temps on any horses that don’t look right. I’ll be asking the other vets working this ride to do the same. That might change as conditions warrant. If your horse is running a fever, I’m going to ask you to leave to protect everyone, includ ing you. The reality is that regardless of whether or not we disinfect stethoscopes between horses, change gloves and wash our hands, it won’t change the fact that the very nature of this sport and this ride in particular requires that a lot of horses will be camping and competing in close proximity, sharing common water and potentially feed sources (because we all know how horses respect sticking to their own buckets and not trying to steal the neighbor’s goodies) and snorting all over each other. This is a very tight campground without a lot of natural water sources available on the trail and my opinion is that we invite potentially more risk to the horses by limiting access to water and hay than we do from EHV-1. As such, it’s the owner’s individual responsibility to decide if the potential risks of EHV-1 and the limited biosecurity being provided are too high for their comfort level. If so, then they should stay home and ho pefully, we’ll see you next year.

Hope to see everyone on June 3 for check-in.

Susan Garlinghouse, DVM