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Horse virus raises concerns

Disease causes quarantines around the state, but no cases are found in Montgomery

Wednesday, Feb. 8, 2006

Equestrians in the county are taking precautions to protect their horses after a virus caused quarantines and several horses were euthanized in other parts of the state.

Last month, an outbreak of equine herpesvirus at Pimlico Race Course prompted Maryland state veterinarians to isolate several barns there and to euthanize at least three horses.

Suspected cases of the virus also caused quarantines at Laurel Park, Bowie Training Center and a private farm in Kent County, where one horse was euthanized, according to the Maryland Department of Agriculture.

The farm — used as an off-track training facility for a horse trainer — received a horse from Pimlico before it was closed on Jan. 10, according to the department.

The virus causes upper respiratory infection and can also have neurological signs. Symptoms include fever and unsteady balance. It is transmitted from horse to horse through coughing and sneezing and direct contact. It does not affect people.

‘‘We actually vaccinated for this about two weeks ago,” said Lynn Woods, director of the equestrian program at the Butler School in Darnestown.

She said people should be reassured that the stable is doing everything possible to keep horses healthy.

‘‘Tons of people are concerned,” said Dr. Richard Forfa, a veterinarian with Monocacy Equine Veterinary Associates in Dickerson. ‘‘The biggest thing is being vigilant.”

There have been more frequent outbreaks of the virus around the country in the last five years, said Dr. Amy Polkes, a veterinarian who specializes in large animal internal medicine with Damascus Equine Associates.

Montgomery County is home to an estimated 13,000 horses and 4,000 residents involved in equestrian activities ranging from trail riding to jumping to fox-hunting, according to Equestrian Partners in Conservation, a county equestrian group.

Polkes said a mutation caused the virus to change from a respiratory infection to one that causes neurological problems. There is no vaccine for the neurological form of the virus, she said, and horse owners should discuss treatments with their vets, including whether to use vaccines for the respiratory form of the virus.

‘‘The disease can spread from farm to farm,” Polkes said. ‘‘But if people take normal precautionary measures, this is not something that should spread all over the place, because the state has done a really good job of containing it.”

Some precautionary measures include disinfecting stalls and items that horses come in contact with, isolating newly acquired animals for 14 to 30 days to prevent introducing diseases to other horses, and keeping show horses and race horses segregated from other horses for at least two weeks after they have been at shows or races, according to the Maryland Department of Agriculture.

Polkes treats animals across the region, including in Montgomery County. She said she does not know of any cases of the virus in the county this year.

Forfa also said he has not heard of any cases in the county this year but said there was an outbreak several years ago at a Poolesville polo farm.

While approximately 80 percent of horses are exposed to the respiratory form of the virus by the time they are a year old, the neurological form is fairly rare, Polkes said.

‘‘There was an outbreak last year and the year before, but in the realm of diseases, it’s not very common,” she said. ‘‘But we are seeing it more than we’d like to.”