EHV May Remain Viable In Water For Three Weeks



A new study has shown that some equine herpes viruses (EHV) can remain viable in untreated water for over three weeks, becoming a source of infection for equids, reports Vet Times.

In many parts of the world, water sources are shared by horses, other equids and other species. If a horse that is actively shedding the EHV-1 virus visits the water and sheds the virus, the virus can remain there long after the animal has left.

The study challenges the long-held belief that the herpesvirus is unstable outside the host; it was believed that they are spread by direct aerosol transmission. However, animals like rhinos and polar bears have contracted EHV though they had no direct contact with horses or their relatives.

Conducted by researchers from the Leibniz Institute for Zoo and Wildlife Research and the Institut für Virologie of the Freie Universität Berlin, the results were reported in Science Daily. The team tested this assumption by spiking the water with EHV under various conditions over three weeks. They then examined  it to see if the viral DNA could be retrieved and how infectious the virus was after having been in the water.

It was shown that the EHV-1 virus remains stable and infectious for up to three weeks. Water temperature and pH played the biggest role in whether or not the virus stayed alive. The addition of soil, which would mimic a natural body of water, actually seemed to “pull” the virus out of the water and into the soil, where it stabilized. This result suggests that EHV-1 can persist for an extended amount of time without infecting other animals. This also shows why some animals can be infected from these bodies of water long after the animal that shed the virus has left.

Read more at Science Daily 

EHV-1: KY Dept. Of Agriculture Issues Revised Protocol For Horses Shipping In From Louisiana

“Earlier this year, in response to the EHV-I outbreak at Fair Grounds Race Track in New Orleans and pursuant to 302 KAR 20:040, we initiated a directive addressing horses originating from or having been stabled in the past 30 days at a premises in Louisiana where EHV-I infection had been diagnosed. The directive required these horses test negative prior to gaining entry onto a Kentucky racetrack or associated training facilities. Our objective in requiring this testing was to help us better define (understand) what if any elevated risks horses originating from these environments might pose to our equine populations here in Kentucky. Unfortunately, the reluctance of trainers to test their horses to qualify for movement to KY has not provided enough testing of those horses to enable us to conclude the risk is not elevated. With the lack of needed evidence, we do today continue to have concern that allowing unrestricted and less regulated movement of those horses to a Kentucky track continues to pose elevated risk (albeit undefined) of disease introduction to our racing environments.

“We did last week initiate conversation with regulators and animal health officials in Louisiana, and they shared their thought and comments that they are not aware of suspicion of EHV1 cases on the track. Additionally, there has apparently been a number of horses moved from Fair Grounds to other racing jurisdictions, and we’ve had no reports of disease events having occurred in those jurisdictions.

“Appreciating, while there remains concern today, we do have an identified need to facilitate interstate movement of horses from those environments to KY race tracks is a safe and efficient manner. Based on the above factors we are today amending our directive by removing the requirement that horses originating from (or having recently resided) Fair Grounds be tested prior to entry onto the track. We will though continue to require these horses (Fair Grounds) to enter Kentucky via an Entry Permit (described below) issued by our office and recorded on the CVI. Copies of this CVI and the EIA testing certificate are to be on file in the track’s stable office and a copy also available in the barn. Post arrival, temperatures for each horse are to be taken three times daily and recorded on an individual log sheet that is to be maintained in the barn. Regulatory and/or track officials will be making periodic visits to the barn.

“Feel free to contact us should you have any question, comment or concern regarding this revised directive.

“Qualifying Horses to Move from Fair Grounds in New Orleans LA onto KY Race Tracks = Effective Wednesday, March 15, 2017

1. A licensed accredited veterinarian shall examine and issue a Certificate of Veterinary Inspection (CVI) within the day preceding a horse’s departure from Fair Grounds*.
2. The veterinarian issuing the CVI shall obtain an entry permit from the Office of KY State Veterinarian 502-782-5901, Monday – Friday, 8:00 am – 4:00 pm (EST).
3. The issuing accredited veterinarian shall record the entry permit number on the CVI.
4. The issuing accredited veterinarian shall record the EHV-1 vaccination on the CVI.
5. A statement is to be included that each horse(s) listed on the CVI has not demonstrated any evidence of infectious illness during the preceding 30 days nor exposure to any such illness.
6. Trainers shall provide to the stable office copies of the CVI and EIA test certificates in addition to keeping a copy of each document in the trainer’s assigned barn. These documents will be presented to regulatory and/or track officials when requested.
7. Animal health officials, racing officials and track officials will be conducting random inspection of horses, the stabling environment and applicable health documents that does include temperature logs during the race meet.
8. These requirements shall remain in effect until further notice.”

*or having been located at Fair Grounds during the 30 days preceding departure for Kentucky

Equine Herpes Virus Confirmed in Denton County Texas

AUSTIN, TX – Texas Animal Health Commission (TAHC) confirmed Equine Herpes Myeloencephalopathy (EHM), the neurologic disease linked to Equine Herpes Virus (EHV-1), in a Denton County barrel racing horse on February 21, 2017.

The horse showed signs of ataxia, loss of coordination of the muscles, and other neurologic signs consistent with EHM when evaluated by a local veterinarian. The premises is under quarantine and TAHC staff is working closely with the owner and veterinarian to implement testing protocols and biosecurity measures.

Prior to confirmation, the positive horse attended barrel racing events at the NRS Arena in Decatur, TX on February 15 and Northside Arena in Fort Worth, TX on February 14. The TAHC has been in contact with event management and veterinarians to ensure enhanced biosecurity measures are taken on the premises and event participants are notified.

While the risk of exposure to the virus was likely low at these events, owners of horses potentially exposed are encouraged to take precautions. Exposed horses should be isolated and have their temperatures monitored twice daily for at least 14 days after last known exposure. If an exposed horse develops a fever or other signs consistent with EHM, diagnostic testing may be performed. Owners should work with their veterinary practitioner to establish appropriate monitoring and diagnostic plans for any potentially exposed horse(s). To learn more, visit

Symptoms of EHV-1 include fever, which is one of the most common clinical signs and often precedes the development of other signs. Respiratory signs include coughing and nasal discharge. Neurologic signs associated with EHM are highly variable, but often the hindquarters are most severely affected. Horses with EHM may appear weak and uncoordinated. Urine dribbling and loss of tail tone may also be seen. Severely affected horses may become unable to rise.

It is important to remember these signs are not specific to EHM and diagnostic testing is required to confirm EHV-1 infection. Many horses exposed to EHV-1 never develop clinical signs. If you suspect your horse has been exposed to EHV-1, contact your veterinarian.

For more information on protecting your livestock from EHV-1, contact your local TAHC regional office To learn more about EHM visit

The equine industry is encouraged to obtain the latest information on this outbreak and other disease events across the country by visiting the Equine Disease Communication Center at:

Final Fair Grounds Horses Released From EHV-1 Quarantine

The final horses remaining in the testing protocols for the Equine Herpes Virus (EHV-1) outbreak at Fair Grounds Race Course & Slots have returned two negative tests and have been released back into the general horse population on the backstretch.

Since the first case of EHV-1 was reported on Dec. 26, any horse testing positive was promptly isolated under the protocols set forth by the Louisiana Department of Agriculture and Forestry and then required after 14 days to return two negative tests, not less than 72 hours apart, before being permitted back into the general horse population.

“The Louisiana Department of Agriculture and Forestry, USDA Veterinary Services and the Louisiana Racing Commission responded to an EHV-1 outbreak at the New Orleans Fair Grounds Race Track on Dec. 26, 2016,” said State Veterinarian Brent Robbins, D.V.M. “On Feb. 14, 2017, the last horse in isolation tested negative and was released after a prescribed observation period. We at the LDAF extend our appreciation to all agencies involved as well as horse owners, trainers and officials at the New Orleans Fair Grounds for their cooperation and understanding in dealing with this outbreak.”

As of Feb. 15, no horses remain in the EHV-1 testing protocols at Fair Grounds and all quarantine restrictions have been lifted by the Louisiana Department of Agriculture and Forestry.

Several Horses Released From Fair Grounds EHV-1 Quarantine; Five Remain Positive

The Equine Disease Communication Center posted the following update on the Fair Grounds Racetrack EHV-1 outbreak on Wednesday: 

On January 23, all horses in isolation at the Fair Grounds racetrack were retested blood and nasal for EHV-1 after at least seven days of isolation. Five of 37 horses remained positive for EHV-1 non-neuropathogenic based only on nasal swab with 32 horses testing negative. Five horses that have completed quarantine were released. Trace-out horses from the receiving barn were released from restrictions following testing and or isolation. Scheduled retesting will continue on isolated horses until release requirements are fulfilled. No new symptomatic horses have been reported in any barns and increased monitoring and biosecurity remain in force.

Fair Grounds Quarantine Could be Lifted Jan. 21

The quarantine of Fair Grounds Race Course imposed due to an outbreak of Equine Herpes Virus-1 (EHV-1) could be lifted as early as Jan. 21, the State of Louisiana Department of Agriculture & Forestry announced in a release Wednesday. The last detected case of Equine Herpes Myeloencephalopathy (EHM)–the more progressed form of the virus–was discovered Dec. 31, 2016. Horses continue to be monitored for both EHM and EHV-1 and, if no new cases are discovered by Jan. 21, phasing out of the quarantine will begin with the 42 Fair Grounds barns in which horses never showed signs of the virus.

“We are encouraged that the disease seems to be contained,” said Agriculture and Forestry Commissioner Mike Strain, D.V.M. “These measures were taken for the health and safety of all horses in the state. We continue to work with the Fair Grounds and Racing Commission to ensure that biosecurity measures will be maintained.”

A total of 39 horses and one barn remain in isolation. Horses who have tested positive for EHV-1 will remain isolated until their tests come back negative, while horses who were exposed but never tested positive will be released on a case-by-case basis.

“After consulting with the state veterinarian, USDA Veterinary Services, LSU and outside experts on infectious diseases, we feel this is a logical plan to allow the release of unaffected horses, Strain added. “The horses that remain in isolation are most at risk. We will continue to monitor these horses until they are in the clear. However, should there be another case of EHV-1 or EHM, we will respond accordingly.”

Delta Downs Ends Quarantine

Delta Downs has ended its quarantine effective Monday, January 16, 2017. A notice sent by  LHBPA Executive Director, Edwin J. Fenasci, states:

“Delta Downs has ended our current quarantine on all horses effective Monday, January 16.

Horses should have a CVI for entry into backside dated within 48 hours prior to arrival.

After Jan. 22nd the normal 30 day issued CVI will be valid for entry.

Should any changes take place to this policy an update will be posted on the overnight.

New Protocols, More Tests: Fair Grounds EHV-1 Outbreak ‘At Least A 45-Day Process’


As the first group of barns at the Fair Grounds Race Course near the end of their state-mandated equine herpesvirus quarantines, the Louisiana Department of Agriculture has been working to define the procedures which will allow those barns to be released from quarantine. Following a meeting earlier in the week between horsemen, USDA representatives, veterinarians, and outside advisors, those protocols have nearly been finalized.

According to assistant state veterinarian Dr. Dianne Stacey, any barn that has held a horse which tested positive for EHV-1, whether it be the wild strain or the neurogenic strain, is automatically quarantined for a period of 14 days. The horse which demonstrated the positive test is placed in isolated quarantine for 21 days; those with the wild strain are kept separate from those with the neurogenic strain.

In order to get out of quarantine, all the horses in the affected barn have to demonstrate two negative EHV-1 tests, spaced at least 72 hours apart, as well as undergo final checks by state veterinarians.

As of Thursday evening, there were a total of 10 horses on the Fair Grounds premises that had tested positive for EHV-1 (two for the neurogenic strain, the others for the wild strain), and six barns were under quarantine (14, 36, 47, 4, 30, and the receiving barn). Also on Thursday evening, the Department of Agriculture updated the Fair Grounds’ voluntary quarantine of the entire backside to a mandatory one, meaning that still no horses are allowed to enter or exit the facility.

The state began the first round of tests on Thursday afternoon, beginning with the first three barns to have entered quarantine. Should the approximately 50 horses stabled in each of those barns all test negative for EHV-1, they would have to again test negative in 72 hours in order to be released from quarantine. If any of the horses test positive for either strain of EHV-1, the 14-day quarantine begins again.

“The rationale for testing has been to get the known positives out of the barn,” said Stacey. “We were under some logistical constraints with the holidays because of all the labs being shut down, which was why we didn’t initially test. We’ve got a better handle now.

“The horses in the quarantined barns have been temped twice a day, every day, and we’ve removed everything that’s even shown a hint of a fever (above 101.5 degrees). So in a perfect world, they’d all come back negative.”

Unfortunately, due to the nature of the EHV-1 virus and its ability to lie dormant in a horse’s system, it appears unlikely that all 50 horses in each barn will be negative. One study found that four percent of a random sampling of 451 horses were positive for the EHV-1 virus (this study did not indicate whether “positive” meant latency or if the horse was actively shedding the virus).

Another study which looked at the necropsies of 132 broodmares indicated that 54 percent had EHV-1 in their lymph nodes (latent). Of those, 18 percent had the neurogenic strain. Of that 18 percent, close to 90 percent had the wild type as well. It adds confusion because horses can have both strains lying latently in their lymph nodes.

Dr. Nathan Slovis, director of the McGee Medical Center at the Hagyard Equine Medical Institute in Lexington, was hired as a consultant on the Fair Grounds outbreak and aided in developing the new protocols. He argues that even though a horse shows no symptoms, the virus’ ability to lie latent may allow the horse to pass it on to its peers. Especially in a racetrack environment, in which horses are constantly in close proximity to one another, the Department of Agriculture has to do its job in order to prevent the virus from spreading.

“When it comes to regulatory agencies, herpes is herpes; it doesn’t matter if it’s wild-type or neurogenic type,” Slovis said. “Everybody keeps thinking ‘oh, wild type, all horses have it, big deal, who cares.’ And the majority of the time, wild type is not a big deal. It may cause abortions and you get some respiratory problems, but it can also cause the neurologic signs.”

The difference between EHV-1 neurogenic and EHV-1 “wild” type viruses is incredibly minute and requires a close look at each’s genetic structure. The wild EHV-1 virus is considered the “normal” version of the virus, without any mutation. In the neurogenic form, a single element of the DNA is mutated; if nucleotide 2254 within the Open Reading Frame-30 gene has a guanine element instead of an adenine, the virus is neuropathic.

According to a study of 48 equine herpesvirus outbreaks over a 35-year period, 83 percent of the symptomatically neurological cases had the mutation, making the virus the neurogenic type. That means that 17 percent of the cases with neurological symptoms had the wild-type strain of the virus.

“It just goes to show you, the regulatory agencies have to take both seriously,” said Slovis. “Even though the majority of the time, the wild-type is going to be more of a nuisance factor, you can’t take that risk at a big place like the Fair Grounds.”

A recent outbreak at the Los Angeles Equestrian Center, said Slovis, was an example of a group of horses with the wild type EHV-1 virus, but eight of the 15 positives at that facility demonstrated neurological symptoms, and one was euthanized. That outbreak lasted just over 60 days.

Local horsemen have expressed serious concerns about the protocols required to get out of quarantine. Many trainers in the affected barns operate small or mid-sized strings of horses, and being unable to race for that long would place them in jeopardy of going out of business. Already, the price of each herpes test has fallen on the horses’ owners, and, at $53 apiece, that adds up.

Preliminary results from Thursday’s testing at Barn 14, the origin of the EHV-1 outbreak, indicate 21 more positives for the wild strain of the virus.

“It’s not going to fix itself in 14 days,” Slovis said. “I’m guessing it’s going to be at least a 45-day process, but I don’t expect any catastrophic events.

“Right now in New Orleans, none of those wild-type positive horses are showing neurologic symptoms. Which means they’re just getting an upper respiratory infection, so they get isolated so that more horses don’t get sick. These horses aren’t going to die, they just don’t want sick horses out on the premises so that they can continue racing normally.”

Along with the state-mandated biosecurity protocols implemented in the quarantined barns, the racetrack has begun to work on additional precautions to improve safety for the rest of the barns on the backside. Dr. Stacey said, among other protocols, the track is considering testing the pony horses for EHV-1.

“We had a consultant come in, and we had a risk analysis and a big discussion,” Stacey said. “It was suggested highly that they be tested because these ponies are under contract with different trainers, but then they go back to a common barn. We did do enhanced biosecurity with footbaths, etc., and we’ve been temping those ponies twice a day, but we did see that they were a little bit higher risk than some of the other quarantined barns. I believe that plans are underway to test them.”

Other measures already in place include disinfecting the starting gates between each race, having grooms bring their own buckets for their horses to the test barn, and not having the horse identifier touch the horses’ lips in the paddock (the grooms are now asked to lift the lip in order to show the tattoo).

In the future, Dr. Stacey hopes the Fair Grounds will work with her department in order to open up another barn on the backside to allow horses to ship in for races, which would help to alleviate the small field sizes that have become prevalent since the outbreak began.

“The bottom line is that they’re going to get over this,” Slovis summed up. “You may see a little spike before things calm down, but they’ve got procedures in place, are implementing additional precautions, and they’ll get over this. It’s just a matter of time.”

Fair Grounds EHV-1: 40 Horses Now Positive, Seventh Barn Enters Quarantine


The Equine Disease Communications Center reports that there are now a total of 40 horses on the Fair Grounds Race Course backside to have tested positive for EHV-1, and that the total number of barns quarantined was increased from six to seven (14, 36, 47, 4, 30, 45, and the receiving barn).

A horse in Barn 45, trained by Andrew McKeever, returned a positive test for the wild type strain, placing Barn 45 under a mandated 14-day quarantine. Also, on Jan. 12, a horse in Barn 20 spiked a temperature of 104 and test results on blood and nasal samples were reported negative for EHV-1; retesting protocols will be followed.

The significant spike in positive tests can be linked to the protocols required for barns nearing the end of their state-mandated 14-day quarantines. Each horse in those barns must test negative for EHV-1 in both blood and nasal samples twice, with the two tests spaced at least 72 hours apart. For more details on those protocols, click here.

The barns tested for future quarantine release were Barn 14, Barn 36, and the Receiving Barn. The results brought back wild-type EHV-1 positives for the following numbers from each barn: Nine (9) horses in Barn 36, nineteen (19) horses in Barn 14 and two (2) horses in the Receiving Barn. It is not yet clear where these latest positives will be quarantined, but all were reported to be asymptomatic at the time of the positive test result, and none had spiked a fever in the previous two weeks.

So far, there are still only two reported positives for the EHV-1 neuropathogenic strain; the other 38 positives are the wild type of the virus.

At this time, Fair Grounds officials are working with the Louisiana Department of Agriculture to secure additional space off property to isolate the horses who have tested positive and are working with the LSRC to further strengthen quarantine protocols and biosecurity measures.

Additionally, the EDCC reported that the Louisiana Department of Agriculture has traced a total of 65 horses that may have been exposed to EHV-1 in the Receiving Barn prior to Jan. 2, and that all of those horses had been isolated and were in the testing process.

The Fair Grounds is under a state-restricted quarantine, and no horses are allowed on or off the premises.

For further updates from Equine Disease Communications Center click here

EHV-1: Restrictions Placed On Louisiana Horses For Upcoming OBS Sale


Due to the equine herpesvirus outbreak at Fair Grounds, officials with the Ocala Breeders’ Sale Company will not allow any horse that has been in Louisiana since Dec. 10 onto its grounds for the upcoming winter mixed sale scheduled for Jan. 25-26.

The BloodHorse reports that OBS becomes the second sale company to place restrictions on Louisiana horses, following the earlier decision by Keeneland officials for the current January sale.

OBS indicated that entry fees would be refunded for horses forced to withdraw from the sale due to the restrictions.

“OBS appreciates the burden this restriction places on some of our consignors and their owners for this sale, but we feel it is important to take these measures in order to provide as safe a sales environment as possible for both buyers and sellers for the January sale as well as our upcoming sales in March, April, and June,” OBS officials said in a statement published by the BloodHorse.

“Additionally, by joining facilities both in Florida and other states, we hope to assist in preventing the spread of this disease, thereby ending this current outbreak quickly. We apologize for any inconvenience.”