EHV-1, EHM

Eight Confirmed Cases of EHV-1 in Colorado Horses

LAKEWOOD, Colo. – The Colorado Department of Agriculture continues to investigate the spread of Equine Herpesvirus (EHV-1) in the state.

As of 5/19/2011, 1pm:
• 8 confirmed cases of horses with EHV-1
• Two horses, which tested positive for EHV-1, were euthanized after showing severe neurological signs associated with the disease.
• 22 suspect cases. Suspect cases are those horses that are believed to have been exposed to EHV-1 but confirmatory tests are still pending.
• 10 quarantine and hold orders have been issued in 6 counties (Bent, Boulder, Larimer, Mesa, Morgan & Weld)

Colorado State Fair Horse Shows Cancelled
Colorado State Fair organizers have voluntarily cancelled three equine events following the spre ad of EHV-1.
• Zamora Roping originally scheduled for May 20-22, 2011. Reschedule date pending.
• Mounted Shooting Regional originally scheduled May 27-30, 2011. Rescheduled for October 7-10, 2011
• Sagebrush Slide Cow Horse Show originally scheduled June 1-5, 2011. Rescheduled for August 10-14, 2011

“We decided to reschedule these events to limit the number of horses traveling to and from our fairgrounds,” said State Fair General Manager Chris Wiseman. “Our horse shows are important to the Fair and to Colorado as a whole and we want to be proactive in protecting our horse community.”

Facts about EHV-1 Vaccines
The common vaccines available for EHV-1 immunization do not protect against the neurological form of EHV-1 disease which is commonly called equine herpesvirus myeloencephalopathy (EHM). These immunizations do protect against the respiratory and abortion forms of the disease.

The EHV-1 vaccines are thought to reduce th e shedding of the virus and may decrease the amount of circulating virus in the system of infected horses. So vaccinations prior to infection may help reduce the severity of an outbreak.

In the face of an EHV-1 outbreak, the value of vaccinating EHV-1 affected horses or exposed horses is questionable and may be detrimental to the horse. When an EHV-1 outbreak occurs, it may be helpful to give an EHV-1 booster immunization in a previously vaccinated, unexposed horse.

Consult with your veterinarian to determine the best vaccination and treatment strategy for your horses in your particular situation.

http://www.aaep.org/pdfs/control_guidel ... 0Virus.pdf
Equine Herpesvirus
Definition
Equine herpesvirus is a common DNA virus that occurs in horse populations worldwide. The two most common strains are EHV-1, which causes abortion, respiratory disease and neurologic disease; and EHV-4, which usually causes respiratory disease only but can occasionally cause abortion.
Respiratory disease caused by EHV is most common in weaned foals and yearlings, often in autumn and winter. Older horses are more likely than younger ones to transmit the virus without showing signs of infection.
Although EHV-1 causes outbreaks of abortion, EHV-4 has only been associated with single occurrences and is not considered a risk for contagious abortions.

EHV-1 myeloencephalitis results from widespread vascular injury after damage to the vascular endothelium of the blood-brain barrier. Neurologic signs result from vasculitis, thrombosis, and necrosis of neurologic tissue. Herpesvirus myeloencephalitis cases occur singly or as outbreaks affecting 20-50% of the population. They may or may not be associated with a previous or ongoing EHV-1 respiratory disease outbreak.

Clinical Signs - please see link http://www.aaep.org/pdfs/control_guidel ... 0Virus.pdf

Thought I'd start a thread for the latest news on the status of EHM, (EHV-1). Will update this thread as info is put forth. Feel free to add to it as well. Keeping your horses home for the next couple weeks would be a very good idea IMO. There simply are no ribbons, no trophies worth your horse's life. Many shows have been cancelled or delayed as have ACTHA trail rides. Good idea!

Myeloencephalopathy (EHM) disease incidents from an event in Ogden, Utah held from April 29 to May 8, 2011, USDA has compiled individual state EHV-1 reports and released the initial national EHV-1 situation report.

A summary of the current situation is as follows:
Owners of horses known to have been exposed in this incident have been contacted by State Animal Health Officials.
Suspect and confirmed cases are reported to be under voluntary or state quarantine.
Known exposed horses are reported to be under either voluntary or state quarantine.

A total of 21 confirmed EHV-1 cases and 12 confirmed EHM cases have been reported in 8 states (CA, CO, ID, NM, OR, TX, UT, WA).
Of the 33 total confirmed EHV/EHM cases, 32 cases are horses that were at the initial event.

There are 7 horses associated with this incident that are dead or have been euthanized.

The complete USDA EHV-1 Situation Report is available here. http://www.aphis.usda.gov/vs/nahss/equine/ehv/ The AHC anticipates USDA releasing the next national situation report at the end of next week. In the interim, the AHC stresses the importance of responsible ownership practices and informed communication among industry organizations. Please see the below links for additional information on EHV-1 transmission risks and disease mitigation strategies.

AAEP website:
General EHV resources through the American Association of Equine Practitioners:
http://www.aaep.org/ehv_resources.htm

Neurologic Disease Guidelines:
http://www.aaep.org/pdfs/control_guidel ... elines.pdf

Equine Herpes Virus:
http://www.aaep.org/images/files/Equine ... 051711.pdf

Biosecurity Guidelines:
http://www.aaep.org/pdfs/control_guidel ... ns%201.pdf

Biosecurity Instructions for Caretakers - English & Spanish:
http://www.aaep.org/pdfs/control_guidel ... grooms.pdf

National Cutting Horse Association (NCHA) website:
For history of the current outbreak and additional outreach materials:
http://www.nchacutting.com/

ACVIM Consensus Statement on EHV-1:
http://onlinelibrary.wiley.com/doi/10.1 ... 0304.x/pdf

http://www.thehorse.com/ViewArticle.aspx?ID=18264 more facts to help stop this disease--main point given is to keep your horses at home!

When I spoke to my horse's vet on Friday, he had just been on the phone with the state vet who said they're going to start lifting bans...

Yeah, I heard that the ban was already lifted. Great news!