Neuropathogenic Equine Herpes Virus Confirmed in Idaho Horses

Neuropathogenic Equine Herpes Virus Confirmed in Idaho Horses
Updated 2/8/18 a.m.

The Idaho State Department of Agriculture (ISDA) has received confirmation of equine herpesvirus myeloencephalopathy (EHM) diagnosed in horses on a premises in Jerome County and a premises in Gooding County. Both premises are privately owned and now are under quarantine.

EHM is caused by a neuropathogenic strain of equine herpes virus (EHV-1) infection and results in neurological symptoms. One additional premises in Gem County also is under quarantine due to a confirmed EHV abortion in a pregnant mare. An epidemiological investigation is under way for the three premises, but no connection between the operations is apparent. The EHV strain affecting the mare in Gem County was a non-neuropathogenic form, which is known to commonly cause respiratory disease as well as abortion in mares.

EHV-1 is highly contagious among horses. The virus poses no health threat to humans. EHV-1 is present in the environment and found in most horse populations around the world. Horses are typically exposed to the virus at a young age with no serious side effects. Research has not yet determined conclusively why horses with EHV-1 can develop the neuropathogenic strain, EHM.

Symptoms frequently associated with EHM infection in horses include a fever greater than 101.5 F, incoordination, hindquarter weakness, lethargy, incontinence and diminished tail tone. The virus is easily spread by airborne transmission, horse-to-horse contact and contact with nasal secretions on tack, feed and other surfaces. People can spread the virus to horses through contaminated hands, clothing, shoes and vehicles. There is no licensed equine vaccine to protect against EHM.

“We encourage owners to contact their veterinarian immediately if they observe any symptoms of illness in their horses,” said Dr. Bill Barton, ISDA State Veterinarian. EHM/EHV is a Notifiable Disease to the State Veterinarian in Idaho. Anyone suspecting or confirming a case of EHM/EHV should call (208) 332-8540 or (208) 332-8570 to report cases.

Horses that may have been exposed to EHV often take several days to demonstrate clinical illness and run the risk of shedding the virus undetected. Exposed horses that travel to shows or exhibitions could expose other horses before disease containment can be implemented.

ISDA urges horse owners to incorporate preventative biosecurity measures while transporting or boarding horses at facilities with regular traffic on and off the grounds and especially where horses are likely to come in contact with new horses such as at a racetrack, rodeo or fairgrounds. Several preventative biosecurity measures are important in minimizing a horse’s risk of contracting the virus:

Disinfect stalls before use,
Never share water or feed buckets and tack or grooming equipment,
Avoid unnecessary contact with other horses.

Additionally, people who work at multiple equine facilities should practice biosecurity measures by washing hands and changing footwear and clothing before entering each facility.


Horse owners are familiar with a Coggins test—that piece of paper required for entry into most horse shows and sales and/or for interstate horse transport. But many overlook the fact that this piece of paper, which serves as proof that the horses has tested negative for equine infectious anemia (EIA), is essential to protecting the health of the national equine population. A number of recent EIA positives in racing Quarter Horse populations in California and Texas has increased the need for awareness about this potentially fatal blood borne disease of horses, donkeys, and mules. Continue reading

Fall Feeding Tips for Horses

As temperatures drop, horse owners should begin to make changes in their horse’s feeding program in preparation for winter. But what alterations are needed? Here are some points to consider when preparing to adjust a nutrition program for the colder weather.


As the temperatures fall, horses will often decrease their water consumption per day. Ensure horses always have access to fresh water, and when temperatures dip below freezing, make sure to check all water sources for ice. Continue reading

AHC Opposes Easing of Import Restrictions on Horses from Saudi Arabia

AHC Opposes Easing of Import Restrictions on Horses from Saudi Arabia

The American Horse Council has opposed the easing of the current 60-day U.S. Department of Agriculture (USDA) import requirement on horses from Saudi Arabia. 

Horses from Saudi Arabia, and all countries affected with African Horse Sickness (AHS), must be quarantined for sixty days before entering the U.S., while horses from non-AHS countries may be admitted with a shorter quarantine period.  The extended period is required to ensure that horses from AHS countries are not infected with AHS, which has a long incubation period.  AHS is a highly contagious and deadly disease that affects horses, donkeys, and mules and has a mortality rate of up to 95% in naive horse populations like that in the U.S. 

In response to a 2009 request by Saudi Arabia to be recognized as free of AHS, USDA studied the status of the disease in that country.  The USDA evaluation used information provided by Saudi Arabia and other sources.  Based on its evaluation, USDA concluded that AHS was not known to be present in Saudi Arabia and that the likelihood of introducing AHS into the U.S. through imports of horses from that country was low.  But USDA also concluded that “the biological and economic consequences of an AHS outbreak in the United States could be high.”  In June, USDA proposed to change the federal import rules to remove Saudi Arabia from the list of countries affected by AHS and allow horses to be imported with a much shorter quarantine period.  

In lengthy comments filed with the Department on August 11, the AHC opposed removing Saudi Arabia from the list of countries affected with AHS.  The AHC maintained that the potential benefits were not sufficient to offset the potential adverse consequences, which included the high mortality rate, up to 95%; the costs of caring for or euthanizing and disposing of sick horses; the imposition of interstate and international controls and travel restrictions on equine movements, which is so important to the industry, that would accompany an outbreak; and the resultant economic affects and lost revenue to the industry in breeding, racing, showing and exhibiting horses.

The AHC noted that most of the U.S.’s trading partners, and particularly the World Organization for Animal Health (OIE), did not recognize Saudi Arabia as AHS-free.  The AHC also questioned whether USDA or the industry itself would have the resources to respond to an AHS outbreak.

The AHC concluded that the USDA evaluation did not make a sufficient case to change the rules and put U.S. horses and the $102 billion U.S. horse industry at risk of AHS.

Vet Mobility Act Signed Into Law

Vet Mobility Act Signed Into Law

On Friday, August 1, President Obama signed into law an American Horse Council (AHC) supported bill, the Veterinary Medicine Mobility Act, making it legal for veterinarians to provide the care necessary to horses away from their licensed place of practice and across state lines.

Previously, the Drug Enforcement Agency (DEA) believed that veterinarians were in violation of the Controlled Substance Act (CSA) and prohibited them from transporting, administering or dispensing any controlled substances which are necessary for the veterinarian when attempting to care for the safety and well-being of the horse beyond their licensed locations.

The new language reads, “a registrant who is a veterinarian shall not be required to have a separate registration in order to transport and dispense controlled substances in the usual course of veterinary practice at a site other than the registrant’s registered principal place of business or professional practice, so long as the site of transporting and dispensing is located in a State where the veterinarian is licensed to practice veterinary medicine and is not a principal place of business or professional practice.”

The AHC is unaware of how the DEA will react to this or whether they will issue new guidance or change their registration process in any way to reflect this new provision.

 The AHC would like to thank Congress and the President for this important legislation that allows veterinarians to continue caring for the well-being of horses without any fear of being in violation of the CSA.

AHC’s Issues Forum Asks “Where Are All the Horses”?

AHC’s Issues Forum Asks “Where Are All the Horses”?

Submitted by admin on Thu, 07/03/2014 – 09:44

On June 24, the American Horse Council held its National Issues Forum, sponsored by Luitpold, the makers of Adequan, in Washington, DC. The forum featured speakers from across the horse industry discussing “Where Have All the Horses Gone.”  Leaders from breed registries, racing, showing, the various disciplines, veterinarians and other stakeholders spoke about the decline in registered horses and the impact on their segment of the horse industry.  Continue reading

Vet Mobility Act Passed by Congress

Vet Mobility Act Passed by Congress

Submitted by admin on Tue, 07/29/2014 – 16:27

Congress has passed the Veterinary Medicine Mobility Act by voice vote. The bill is sponsored by Representatives Kurt Schrader (D-OR) and Ted Yoho of Florida (R-FL), both of whom are veterinarians and Senator Angus King (I-ME) and Jerry Moran (R-KS). The AHC has strongly supported this bill. Continue reading

Senate Committee Approves PAST Act

Senate Committee Approves PAST Act

Today, the Senate Commerce, Science and Transportation Committee approved the Prevent All Soring Tactics Act (PAST Act) (S.1406).  The PAST Act would strengthen the Horse Protection Act (HPA) and finally end the soring of Tennessee Walking Horses, Spotted Saddle Horses, and Racking Horses. The AHC has been working to advance this important piece of legislation in both the Senate and House and is pleased it is one step closer to passage.   Continue reading


Submitted by  Dr. Marilyn Simunich

All horses racing in Saskatchewan’s Northwest Pony Chuckwagon and Chariot Association must be tested for the deadly equine infectious anemia [EIA] before they will be allowed to race.
Darren Dyck, the association’s new president, said Coggins tests have been made mandatory for racehorses in an effort to halt spread of the disease. Continue reading