More EHV-1 Cases, Deaths Rise to 8, 2nd Cutting Horse Show Cited

10 years ago StraightArrow Comments Off on More EHV-1 Cases, Deaths Rise to 8, 2nd Cutting Horse Show Cited
Health workers during an equine herpes virus outbreak in Florida four years ago. © Ken Braddick/


The number of horses that have died or been euthanized in the equine herpes virus outbreak has risen to eight with confirmed new cases reported Sunday, including one that competed only at a California show and not the Cutting Horse championships in Utah early this month that previously had been identified as the sole source of the outbreak.

The latest death was reported in Utah, the first in the state where the outbreak apparently began at the National Cutting Horse Western Championships in Ogden early this month. The Utah government reported the horse was being treated for EHV-1 but when it could not get up it was humanely euthanized.

Seven deaths from the virus previously reported by the U.S. government were in Arizona (1), California (1), Colorado (2), Idaho (2) and New Mexico (1) in the outbreak of the highly contagious virus that has impacted a huge swath of the western United States and Canada.

The California Department of Food and Agriculture gave its latest tally as 17 confirmed cases of EHV-1/EHM, 16 that participated in the Ogden, Utah, event and one in a horse that took part only in a cutting horse event in Bakersfield, California on May 13. The state agency also reported cases have been confirmed in Los Angeles, suburban Ventura county and Marin County, a bedroom suburb of San Francisco.

The latest updates compiled by from state government reports show that in addition to the deaths, cases of EHV-1 or EHM by state: California (17 confirmed), Colorado (9 confirmed, 22 suspected); Idaho (1 confirmed, 13 suspected), Montana (1 suspected), Nevada (3 suspected), New Mexico (2 confirmed, 4 suspected), Oklahoma (1 suspected), Oregon (2 confirmed), Texas (1 confirmed, 1 suspected), Utah (7 confirmed, 3 suspected), Washington (3 confirmed, 4 suspected) and Wyoming (1 suspected).

Equine Canada reported another four cases in the provinces of British Columbia and Alberta, all among horses that competed at the Utah championships.

The new cases bring to 46 the number of confirmed cases, plus eight deaths from horses participating in the championships in Utah and the Bakersfield, California, event.

No horses in other disciplines are reported to have been affected.

However, the outbreak of the highly contagious virus that does not affect humans but is spread by contact up to 30 days after contact has been reported by major news organizations in the United States including The Wall Street Journal and other national media.

Several horse shows–including dressage competitions–and clinics were cancelled or postponed throughout western states, including clinics for jumpers and reining in Colorado. Three Oregon Dressage Society events were postponed and a fourth was moved. U.S. Equestrian Federation sanctioned competitions Las Vegas Dressage Spring Fling III scheduled for Saturday and Sunday and a one-day competition in Kirkland, Washington, canceled because of the outbreak.

However, two competitions in California, a CDI1* at Woodside and a California Dressage Society show at San Juan Capistrano, went ahead.

Colorado and Wyoming have imposed restrictions on horses entering the state, but other states with horses affected by EHV have not.

An outbreak of the equine herpes virus in South Florida in December, 2006, just weeks before the start of the winter dressage, hunter-jumper, polo and Thoroughbred racing circuits led to the deaths of six horses.

Due to the huge area directly impacted by the latest outbreak–the eight states where confirmed or suspected cases have occurred is almost one-third the total land mass of continental United States–the U.S. Department of Agriculture agreed to a request by the American Horse Council and American Association of Equine Practitioners to coordinate information gathering and distribution among states.

Biosecurity measures recommended for horses who attended the Odgen event or may have come in contact with horses affected include:

-Isolate exposed horse a minimum of 30 feet away from all other horses (round pen if necessary) for 21 days;
-Monitor temperature twice a day for 14 days;
-Immediately report temperatures over 102F (39C) to your private veterinarian;
-Use separate equipment, bucket, halters/leads for isolated horse;
-Wear protective clothing when handling isolated horse–coveralls, boot covers, gloves. Do not use same clothing with other horses;
– Ideally, use separate personnel for isolated horses, and
-Restrict movement.

Key to limiting the disease from spreading is Isolation of sick horses. Sick horses are shedding virus and should be removed from exposing additional horses.

Symptoms can include fever, sneezing, slobbering and other mild symptoms. Serious cases of the disease are rare, but can include staggering, hind-end paralysis and even death of the horse.

The virus can usually survive for about a week on surfaces, though under the optimum conditions could last as long as 30 days.

The American Association of Equine Practitioners said:

• There is no specific treatment for EHV-1, although antiviral drugs (i.e. valacyclovire) may have some value before neurological signs occur.

• Non-specific treatment may include intravenous fluids, and other appropriate supportive therapy.

• The use of anti-inflammatory drugs (NSAIDs) is strongly recommended.