Source:  Various

States:

Arizona:

The Arizona Department of Agriculture (ADA) received laboratory confirmation last night of Equine Herpes Virus (EHV -1) infection in an Arizona horse that showed severe neurological disease. The owners of the affected horse, under the direction of an attending veterinarian, have restricted animal movement to prevent the spread of disease to other horses. They are closely monitoring the remaining exposed horses.

California:  

Barnmice News Update

Colorado:

UPDATE: As of 5/25/2011, 12:30 pm:

• 9 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. NOTE: Suspect cases are those horses that are believed to have been exposed to EHV-1, show consistent clinical signs of the disease, and have confirmatory tests pending OR are horses showing clinical signs and located in a quarantined facility with a horse confirmed to have EHV-1 in which case, the decision to test will be made by the horse owner and their veterinarian. Release of the quarantined facilities will require EHV-1 testing to assure freedom of the disease. 
• 12 quarantine and hold orders have been issued in 8 counties (Bent, Boulder, Garfield, Gunnison, Larimer, Mesa, Morgan, & Weld).

Colorado State Fair organizers have voluntarily cancelled three off-season fairgounds horse events following the spread 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

Florida:

There is one farm in Alachua County, which is under state quarantine, that has had two horses euthanized due to complications of EHV-1 infection (one case suspected and one confirmed). We believe that the index case occurred on the quarantined farm due to reemergence of a latent infection and that no exposure has occurred off the affected premises.

 

We will continue to monitor the situation in our western states and plan to post information on our Web site weekly, or more frequently, if needed.

Idaho:

As of 5/25/2011, 1:00pm  

• No new cases of suspected or confirmed EHV-1 infection in Idaho horses have been reported to the Idaho State Veterinarian during the past 24 hours . 

Illinois:

According to event records, two horses owned by Illinois residents participated in the event. One horse has returned to Illinois and one horse remains stabled out-of-state. Both owners have been contacted by the Department and both horses are clinically healthy as of 05/16/11.

One Kansas horse was at the Ogden, Utah, event where the virus is thought to have originated, but that particular horse did not return to Kansas. The animal is under quarantine outside of Lincoln, NE.

Montana horse owners who attended the event, or who have horses that share facilities with horses that attended the event, should carefully monitor the health of their horses for signs of the disease and/or any unusual behavior. Horse owners who suspect a problem should immediately contact their local veterinarian.
“We’re hopeful that no Montana horses were infected,” said state veterinarian, Dr. Marty Zaluksi. “The incubation period is typically 2-14 days, so we may be in the clear.”

Sixteen horse owners and 30-35 horses from Montana attended the event. No cases of the disease have been reported within the state.

In an effort to be proactive and provide the maximum safety to horses across the country, NCHA affiliate organizations and show producers in Montana, Oregon, Oklahoma, Texas, California, Wyoming, New Mexico, Washington and Nevada have cancelled previously scheduled shows for the weekend of May 20 – 22, 2011.

An NCHA/American Quarter Horse Association event scheduled for June 4-5 in Dillon has also been cancelled; a decision about an event scheduled for July will be made at a later date.

On May 16, Missouri's State Veterinarian was notified that three horses had returned to a Boone County farm after being exposed to Equine Herpesvirus Myeloencephalopathy during a show in Odgen, Utah. The horses were immediately isolated and placed under a veterinarian's care.
In additional, Missouri's State Veterinarian placed a hold order on the farm May 16, preventing animals at the facility from being transferred elsewhere.

Test results were negative for isolates of the EHV virus, and the horses showed no symptoms of infection.

The Nevada Department of Agriculture is reporting the two additional laboratory confirmed case of Equine Herpes Virus 1 (EHV-1) in Nevada resident horses. The two horses are located in Washoe County and were exposed to two horses that attended the 2011 National Cutting Horse Association Western National Championships in Ogden, Utah earlier this month. The event horses did not develop disease. The two cohorts exhibit neurological symptoms.This brings the number of affected horses in NV up to three.

Presently in New Mexico, three premises are under quarantine as a result of active cases of EHV-1. All three premises have had cases of the neurological form of EHV-1, also known as Equine Herpes Myeloencephalopathy (EHM).
One horse has died, two horses are clinically ill and one horse has recovered. The last case in New Mexico was reported on May 20, 2011. All other horses on these quarantined premises are under close observation and are being monitored by their farm veterinarians.
Currently, all cases of EHV-1 diagnosed across the western United States have been associated with the horse event in Utah. All known exposed horses are under observation and restricted movement. There has not been any evidence to suggest that any exposure has occurred in race horses.
It appears that the outbreak is under control; however due to additional exposures either at other events or horses that were exposed, but have not been identified, it has been determined that an additional 7 – 10 days is needed before normal equine movement can resume.
It is recommended that major or large equine events not be conducted for the next 10 days.
A national EHV situation report will be updated by USDA on May 26, 2011. The New Mexico Livestock Board will evaluate events and take appropriate action on or around June 1, 2011.

Currently, Oregon has three horses that have tested positive but did not show clinical signs of the neurological herpes virus (equine herpesvirus myeloencephalopathy) or EHM. A fourth horse developed neurological signs and was euthanized. The test positive horses are in Clackamas, Deschutes and Umatilla counties. The horse with neurological signs was also from Clackamas county. These horses are directly linked to the cutting horse event held in Utah from April 30 through May 8, 2011. A number of other cases have been confirmed in surrounding states including, Washington, Idaho, California and Colorado. EHM is a highly contagious neurological virus that can cause severe neurological symptoms in horses.

Equine Herpes Virus (EHV-1) Confirmed in South Dakota
The South Dakota Animal Industry Board (SD AIB) received laboratory confirmation today (5/20) of Equine Herpes Virus (EHV-1) infection in a Gregory County horse. The affected horse and others on the premises have been quarantined to prevent the spread of disease to other horses.
The horse was not taken to the National Cutting Horse Association’s Western National Championships in Ogden, Utah, April 30-May 8, 2011. Utah, Idaho, Colorado, California and New Mexico animal health officials have reported suspected cases of EHV-1 infection in horses that were at the Ogden event.

from 5-18-11

South Dakota State Veterinarian Dr. Dustin Oedekoven says South Dakota horses that attended the show in Utah are not showing symptoms of the disease.

“The owners have been contacted and advised to isolate exposed horses for three weeks, follow good biosecurity practices and watch for possible clinical signs”, Oedekoven said.

5-25-11 TAHC officials have started releasing primary traced horses and their cohorts (stablemates) that attended the Ogden, Utah, NCHA event. Currently 16 known horses in Texas that attended the event and 185 cohorts (stablemates) remain under movement restrictions. There are a total of ten premises that have been exposed and those premises are in the following counties: Randall, Parker, Jack, Kerr and Mills counties.

5-24-11 Currently 18 known horses in Texas that attended the event and 189 cohorts (stablemates) remain under movement restrictions.

5-23-11 The single “suspect” case that was reported Thursday, May 19, from Jack County tested negative for EHV-1, however was euthanized due to the severity of its unrelated illness.

5-19-11 Texas Animal Health Commission (TAHC) officials are continuing to trace exposed horses that attended the National Cutting Horse Association (NCHA) Western National Championships event that ended on May 8 in Ogden, Utah. There are currently 26 known horses in Texas that attended the event. Those 26 horses and a total of 323 more cohorts (stablemates) of the 26 are currently being held under movement restrictions across the state.
Texas has currently only detected one confirmed case. That horse sought treatment at a veterinary clinic in far West Texas and has subsequently returned to New Mexico where it originated. A second horse located in Jack County has been classified as “suspect” and is pending further diagnostic testing. The TAHC is following the U.S.D.A. guidelines for clinical and suspect cases which have very specific criteria to meet the case definition, and for now suspect and confirmed cases will be the two types of cases reported.

5-18-11 Texas has only one confirmed clinical case of neurologic EHV-1 so far, which was a horse originating from New Mexico that sought treatment at a vet clinic in West Texas earlier this week. The horse has since been returned to New Mexico and is now quarantined on its premises of origin.

There have been no new confirmed cases or suspect cases reported by Utah veterinarians today. All suspect and confirmed cases will continue to be under quarantine for 28 days following the cessation of neurological symptoms.
There are still only four (4) quarantined private facilities (Box Elder, Davis, Kane, and Utah counties) with a total of seven (7) confirmed cases and eight (8) suspect cases on these premises. To date, two of the Utah cases were humanely euthanized after going down and being unable to return to their feet.

Update 5/24/2011: Positive Cases in Washington State = 6
Counties with confirmed EHV-1 cases: Thurston, Spokane, Chelan, Asotin, Whitman (2)
Confirmed deaths to date = 0

Unconfirmed report of an additional case at WSU Veterinary Teaching Hospital

5-17-11 Two horses owned by Wisconsin residents, but kept in another state, competed in Utah. They did not enter Wisconsin after the competition.

Neurotropic Equine Herpesvirus-1 (nEHV-1) in Alberta 5-20-11
Case Summaries:

There is a confirmed neurologic case of nEHV-1 in an Alberta horse that showed neurologic signs on May 1, 2011 and was isolated at that time. This horse did not attend the cutting horse show in Ogden that has been associated with the US outbreak of the disease; however, it had attended cutting horse events in Alberta. This horse has been under veterinary care and is recovering very well. The origin of the source of contact for this horse remains unknown.
There is a second confirmed case of nEHV-1 in another Alberta horse that first developed signs of fever and respiratory disease on May 14, 2011. There are no neurologic signs in this horse. This horse had contact with horses and tack that had previous contact with horses at the Ogden show. This horse is under treatment and isolation at this time.
There is a third confirmed case in an Alberta horse that first developed signs of fever and respiratory disease on May 16, 2011. Again, there are no neurologic signs in this horse. This horse travelled to the show in Ogden and returned to Canada on May 15, 2011. This horse is under treatment and isolation at this time.
Two more suspect cases of Alberta horses with signs of respiratory disease and fever have laboratory tests pending. These horses are under isolation and treatment at this time.

Exposure, but no positive cases:

British Columbia, Wyoming

Determination of no exposure:

Hawaii, Indiana, Kentucky, Maine, Maryland, New Jersey, New York, South Carolina, Tennessee, Virginia, (No horses attended the Utah cutting, no horses exposed)

No Information:

North Dakota

(Material quoted from state or provincial agriculture  websites.)