Source:  Various

Two states' veterinary departments and one major veterinary teaching hospital have released information regarding the EHV-1 outbreak that originated in Utah.  Following are the announcements:

From Callifornia:

Equine Herpes Virus

ALERT

May 13, 2011

A recent disease outbreak of Equine Herpes Myeloencephalopathy (EHV-1) has been traced to horses who attended the National Cutting Horse Associations’ Western National Championships in Odgen, Utah on April 30 – May 8, 2011. California horses who participated in this event may have been exposed to this EHV-1 virus.

The California Department of Food and Agriculture encourages owners of horses who participated in the Odgen, Utah event to monitor their horses for clinical signs of disease. A rectal temperature in excess of 102F commonly precedes other clinical signs. Therefore, we are urging owners to take temperatures on each individual horse(s) twice a day. If a temperature above 102F is detected contact your private practitioner immediately. Laboratory submission of nasal swabs and blood samples collected from the exposed horse can be utilized for virus detection and isolation.

The EHV-1 organism spreads quickly from horse to horse and the neurologic form of the virus can reach high morbidity and mortality rates. The incubation period of EHV-1 is typically 2-10 days. 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. Treatment may include intravenous fluids, anti-inflammatory drugs and other appropriate supportive treatment. 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 illness 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.

For Additional Information:

• Equine Herpes Myeloencephalopathy Brochure
• CDFA Equine Herpes Myeloencephalopathy Fact Sheet
• USDA Resources
• American Association of Equine Practitioners Fact Sheet

 

Contact us for more information:
California Department of Food and Agriculture
Animal Health and Food Safety Services, Animal Health Branch
1220 N Street, Room A–107
Sacramento, California 95814
Telephone: (916) 654–1447
Fax: (916) 653–2215
or send an email to: ahbfeedback@cdfa.ca.gov

media release Colorado Department of Agriculture
                             www.colorado.gov/ag
FOR IMMEDIATE RELEASE
May 13, 2011
Contact:    Christi Lightcap, (303) 239-4190, Christi.lightcap@ag.state.co.us
                 
Equine Herpesvirus Confirmed in Two Colorado Horses
 
LAKEWOOD, Colo. – The Colorado Department of Agriculture is investigating two confirmed cases of Equine Herpesvirus (EHV-1) within the state.  Two quarantines have been placed on two Weld County premises.
 
One horse was euthanized after showing severe neurological signs associated with the disease and the second horse is currently under observation in a biosecure location.
 
“The Department is taking quick and appropriate actions to control and mitigate this disease,” said State Veterinarian, Dr. Keith Roehr.  “We will continue to trace the movement of these horses and those horses they came into contact with in order to protect Colorado’s equine industry.”
 
Both diagnosed horses had recently attended the National Cutting Horse Association’s Western National Championships in Ogden, Utah.  The Colorado Department of Agriculture is working with the Utah State Veterinarian to investigate the location as a point of interest for the infection.
 
EHV-1 is not transmissible to people; it can be a serious disease of horses that can cause respiratory, neurologic disease and death. The most common way for EHV-1 to spread is by direct horse-to-horse contact.  The virus can also spread through the air, contaminated equipment, clothing and hands. 
 
Symptoms include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy, and the inability to rise. While there is no cure, the symptoms of the disease may be treatable.
 
Additional Resources:
• A Guide To Understanding the Neurologic Form of EHV Infection
• USDA Animal Plant Health Inspection Service Resources
• American Assoc. of Equine Practitioners Fact Sheet
 

Important Announcement about Equine Herpes
The Washington State University Veterinary Teaching Hospital is entering a period of voluntary isolation for equine and camelid patients.  This is in response to a patient that was confirmed to be shedding Equine Herpes Virus type 1 (EHV-1).   In the past week there have been 2 confirmed cases of EHV-1 in Colorado in horses that competed at the National Cutting Horse Association Western National Championships in Ogden, Utah.   A horse admitted to the Washington State University Veterinary Teaching Hospital for evaluation of unrelated problems was found to have competed at the show.  Subsequent diagnostic testing confirmed that the horse was positive for EHV-1.   Due to the potential for spread of the virus, access to the VTH is currently restricted.  During this time, no new equine or camelid patients may be admitted to the hospital except for critical emergencies.  It is expected that the period of isolation will last at least 2 weeks.   There are currently no horses exhibiting signs of EHV-1 at WSU.    Equine Herpes Virus does not affect cattle, sheep, goats, pigs or birds, and the remainder of the VTH remains open.  There is no risk of transmission to people.
We are taking every precaution to ensure the health and well-being of animals.  We hope that the following information will be helpful .
Equine Herpes Virus is a common virus in equine populations worldwide.   There are several strains of the virus, with EHV-1 and EHV-4 being most often involved in clinical disease.   EHV-1 can cause respiratory disease, abortion and neurologic disease, while EHV-4 typically causes respiratory disease.   Neurologic disease, which is generally caused by specific strains of EHV-1, is called equine herpesvirus myeloencephalopathy (EHM).  
What are the common clinical signs of EHV?
Fever is one of the most common clinical signs and often precedes the development of other signs.  Respiratory signs include coughing and nasal discharge.  Abortions caused by EHV generally occur after 5 months of gestation.   Neurologic signs associated with EHM are highly variable, but often the hind end is most severely affected.   Horses with EHM may appear weak and incoordinated.  Urine dribbling and loss of tail tone may also be seen.   Severely affected horses may become unable to rise.   
It is important to remember that none of these signs are specific to EHV, and diagnostic testing is required to confirm EHV infection.  Also, many horses exposed to EHV never develop clinical signs.
How long is the virus shed once a horse is infected?
Shedding by the respiratory route typically lasts for 7-10 days, although occasionally it may persist longer.
How is EHV spread?
EHV  is transmitted primarily by aerosol and through direct and indirect contact.  Aerosol transmission occurs when infectious droplets are inhaled.  The source of infectious droplets is most often respiratory secretions.   In the case of abortions, virus may be present in the placenta, fetal membranes and fluid, and aborted fetuses. 
Direct horse-to-horse contact is a common route of transmission of the virus, but Indirect transmission is also important. This occurs when  infectious materials (nasal secretions, fluids from abortions, etc.) are carried between infected and non-infected horses by people or fomites (inanimate objects such as buckets, etc).
What should I do if my horse has been exposed to EHV?
If you suspect your horse has been exposed to EHV, contact your veterinarian.  In general exposed horses should be isolated and have their temperatures monitored twice daily for 10 days.  If an exposed horse develops a fever, diagnostic testing should be performed.  While there are several testing methods available, the most frequently recommended test is a PCR to detect the viral genetic material done on a nasal swab.
How do I get more information about EHV?
The American Association of Equine Practitoners and the USDA have information on their websites related to EHV and biosecurity:
 
http://blogs.usask.ca/EHRF/EHV%20fact%20sheet-1.MAR.20.pdf
http://www.aaep.org/health_articles_view.php?id=222
http://www.aphis.usda.gov/vs/nahss/equine/
http://www.aaep.org/ehv.htm
Last Edited: May 15