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

The Owyhee Fandango: It's On!

Monday May 23 2011

Less than a week till the 3-day Owyhee Fandango endurance ride and it's one thing after another: EHV-1 outbreak, cancellations, having to re-route trails because of too many cows out and high water, having to re-route trails because of cancellations and therefore not enough riders to pay for the extra vet we'd need at an out vet check, trail sabotage...


And Steph just got word this morning from the manager of the Sierra del Rio Ranch, where we often have a vet check and eat and rest in their lush grassy fields, and where we'd be riding through with a water stop on Day 3 this year, and who are normally happy to see us, said that on advice of their veterinarian, it was better if they didn't have horses coming through.


That decided it. Steph said, "There's no way I'm NOT having an endurance ride! I've never cancelled an endurance ride, and I'm not cancelling the Owyhee Fandango! If it's just us riding, then it's just us riding!"

Head veterinarian Robert Washington issued a sensible statement yesterday:

"The purpose of this post is to provide facts about EHV-1 and the current outbreak. I am not telling you to stay home nor am I telling you to go to this ride or other events. I am merely trying to provide correct current information on which everyone can make their own decision. It is amazing how fast information can get out and around via all of our technologies. The only down side of that, is there is a lot of misinformation swarming about the disease outbreak.

I will start with some information about the EHV-1 virus. Since it is a herpes virus, it can live dormantly in asymptomatic horses for a long period of time. These horses can spread the virus when stressed. This is the reservoir for the virus to persist. This virus has been known about for a long time, before if was found to be a herpes virus, it was called a rhino virus. Historically, symtoms caused by this virus are cough, nasal discharge, fever, abortion, and in a few cases, neurologic disease. Contrary to what some would have you believe, this virus is very common and is the cause of a lot of the "colds" horses can get from time to time. Over the last few years, a neurotropic strain of this virus has been identified, and this strain has caused a number of the outbreaks over the last 10 or so years.

So, this virus and disease syndrome are not some new "superbug". A percentage of horses carry this virus longterm. A study was done on thoroughbred broodmares, and 40-50% were found to be carriers. Again, this virus is very common. Most horses over 2 or 3 have seen the virus at some point in their lives. These outbreak situations occur with a shedding horse due to the stress of travel and showing, and exposure to a large population of horses. Horse shows and events are always a risk of disease transmission. Everything from flu, strangles, EHV and others can be spread in these gatherings of animals.

This virus is not very hardy outside of the horse. It can be kept alive in a laboratory situation for around 30 days. Under real conditions, that period is less than 7 days. It is killed very easily by 10% bleach solutions, common disinfectants, and alcohol (hand sanitizers). The virus can be spread up to 35-50 feet via aerosol under ideal conditions. The virus is only spread via nasal secretions. In reality, this virus is not spread as easily as some information would have you believe.

At this time, the cases from this outbreak (there is another separate outbreak in Florida) are confined to farms exposed to horses that were at the Ogden show. Yes, there are new cases, but they are still on the farms where horses returned from Ogden. In reality, the risk of an endurance horse that has not been at an infected facility to catch EHV-1 at an endurance ride is no greater than it ever is.

It is always advisable to observe your horse closely prior to travel. Take his or her temperature prior to leaving. If they have a fever, nasal discharge, cough, or "don't seem quite right", it is always recommended to not travel.

At this time, there are no travel restrictions. Wyoming and Colorado have changed their health certificate requirements, but are open to travel. At this time the Canadian border is open. I will have a health certificate book at the ride in case we need to write some for people to return home, and I will check travel requirements before offices close on Friday.

If you choose to come to the ride, I would ask that you monitor your horse closely. All horses will have their temperature taken as part of the pre-ride check. Given the nature of what endurance horses due, that will be the only time they will have their temperature taken, as I know they will get hotter than normal during the rides.

To end all this rambling, disease spread is always a risk in gatherings of horses. It is my opinion that the risk of your horse getting EHV at this or any ride are no more than they ever are."


Well said.

For us, we're still getting ready for the ride. It just means changing some trails to accommodate the situations. Which means more ATVing (for Steph), more riding and hiking for us to flag trails.


As if we needed any excuses to ride and hike around here. : )

(and PS - just before hitting the Publish button, Steph sent out an email saying we DO have permission to use the Sierra del Rio ranch now - the Petroglyph trail is back on for Sunday!)

EHV-1 Outbreak in the Western US and Canada

Tuesday May 17 2011

An outbreak of neurologic Equine Herpes Virus (EHV-1) started at the NCHA Western National Championships in Ogden, Utah which took place on April 28-May 8. Horses had left the event before participants were notified of the disease.

It is highly contagious and any exposed horses and facilities must be quarantined to stop the spread of the disease. It could become very serious.

Thehorse.com defines EHV-1: Equine herpesvirus is highly contagious and can cause a variety of ailments in horses, including rhinopneumonitis (a respiratory disease mostly of young horses), abortion in broodmares, and myeloencephalopathy (evident in the neurologic form). The virus is not transmissible to humans. Clinical signs of the neurologic EHV-1 form include fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence. The virus is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions.

As of today, May 17, "The number of horses confirmed or suspected to have EHV-1 remains on the rise, with several states reporting cases," according to Thehorse.com.

So far there have been 6 EHV-1 positive horses in California, 2 in Colorado (one was euthanized; a second horse was euthanized after displaying severe signs although a positive diagnosis has not been confirmed), 1 in Washington.


The AAEP released the following information:
URGENT RESPONSE INFORMATION AND RESOURCES

Currently, there are numerous reports of equine herpesvirus myeloencephalopathy (EHM) affecting horses and farms across the U.S. and Canada. This outbreak appears related to initial cases at a cutting horse show in Ogden Utah, which was held from April 29 - May 8. Horses at that event may have been exposed to this virus and subsequently spread the infection to other horses. While the true extent of this disease outbreak is uncertain, there is clearly a very significant elevated risk of EHM cases at this time.

At this time control of the outbreak is critically dependent on biosecurity. Laboratory submission of nasal swabs and whole blood samples collected from the exposed horse can be utilized for virus detection and isolation. Please consider testing any suspected cases. The EHV-1 organism spreads quickly from horse to horse but typically only causes neurological disease sporadically. However, in an outbreak of EHV-1 neurologic such as we are experiencing now, the disease can reach high morbidity and case fatality rates. The incubation period of EHV-1 infection is typically 1-2-days, with clinical signs of fever then occurring, often in a biphasic fever, over the following 10 days. When neurological disease occurs it is typically 8-12 days after the primary infection, starting often after the second fever spike. In horses infected with the neurologic strain of EHV-1, clinical signs may include: nasal discharge, incoordination, hind end weakness, recumbency, lethargy, urine dribbling and diminished tail tone. Prognosis depends on severity of signs and the period of recumbency.

There is no specific treatment for EHV-1, although antiviral drugs (i.e. valacyclovire) may have some value before neurological signs occur. Non-specific treatment may include intravenous fluids, and other appropriate supportive therapy; the use of anti-inflammatory drugs (NSAIDs) is strongly recommended. Currently, there is no equine vaccine that has a label claim for protection against the neurological strain of the virus. Horse-to-horse contact, aerosol transmission, and contaminated hands, equipment, tack, and feed all play a role in disease spread.

However, horses with severe clinical signs of neurological EHV-1 infection are thought to have large viral loads in their blood and nasal secretions and therefore, present the greatest danger for spreading the disease. Immediate separation and isolation of identified suspect cases and implementation of appropriate biosecurity measures are key elements for disease control. In order to assist you and your clients further, visit online here http://list.aaep.org/t/68400/2510/113322/0/ for Frequently Asked Questions, resource information from the AAEP, USDA, state and provincial animal health departments, and other related information regarding this outbreak and the disease. For additional questions, please contact Keith Kleine, AAEP director of industry relations, at (800) 443-0177 or kkleine@aaep.org.

Sincerely,

William Moyer, DVM
2011 AAEP President
Raising the Standard in Horse Health

American Association of Equine Practitioners
4075 Iron Works Parkway
Lexington , KY 40511
859-233-0147

****

Remember the devastating Equine Influenza in Australia in 2007? It's better to be overly cautious than to risk a severe outbreak, as there is no vaccination, the disease is easily transmissible, highly contagious, and can be deadly.


It is recommended all horse owners follow these four biosecurity measures on their operations:

* require individuals to wash their hands before and after contact with each horse;
* avoid contact with other horses;
* disinfect boots and change clothes that come into contact with other people’s horses;
* isolate horses returning from shows for 2-3 weeks.

If you have any reason at all to think your horses could have been exposed, monitor your horses for any symptoms, check for elevated temperatures (above 102) twice daily, hunker down for a week or so, and contact your veterinarian immediately if you see any symptoms (fever, ataxia - incoordination, weakness or paralysis of the hind limbs, and incontinence).

Equisearch has good up-to-date information on the disease, its progress and monitoring:
http://blogs.equisearch.com/horsehealth/?utm_source=eqs&utm_medium=nl&utm_campaign=eqs .

TheHorse.com will have reliable information:
http://www.thehorse.com/ViewArticle.aspx?ID=18257