UPDATE: Four symptomatic horses in stable condition at equine medical center

Four horses that are being held in the Biosafety Level 2 isolation unit at Virginia Tech's Marion duPont Scott Equine Medical Center are in stable condition after exhibiting symptoms of the Equine Herpesvirus Type 1 (EHV-1). According to hospital officials, two of the horses have tested positive for the virus while results of tests performed on the remaining two animals are expected early next week.

Editor's note: The Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) and Virginia Cooperative Extension will present "Update on the Neurological Equine Herpesvirus Type-1 (EHV-1) Outbreak in Virginia" on Tuesday, March 6, 2007 as part of an ongoing "Tuesday Evening Talks" lecture series.

Post-mortem tests taken on a fifth horse that was euthanized at the center for an unrelated disease on Feb. 13, also came back positive for the virus leading to a total of three positive tests at the center for EHV-1.

According to Dr. Nathaniel White, Jean Ellen Shehan Professor and Director of the Marion duPont Scott Equine Medical Center, it is believed that the EHV-1 infection began when on Feb. 7, a horse admitted for an unrelated emergency, subsequently underwent surgery and was stalled in a barn with other horses.

“At the time, the horse did not have a fever and was not exhibiting any symptoms of neurologic distress,” said White. “However, on Sunday, Feb. 11, four days after admission, that horse developed a fever and neurological signs and was immediately placed in our isolation unit.”

The hospital’s veterinarians performed a variety of tests to identify the cause of the horse’s symptoms, and on Feb. 16, one of those tests came back positive for EHV-1.

“Because this is a very contagious virus that can cause fatal neurologic disease, we elected to close portions of the hospital immediately and to contact owners of horses with any potential exposure to the virus during the incubation period,” explained Dr. Martin Furr, Adelaide C. Riggs Chair in Equine Medicine at the Marion duPont Scott Equine Medical Center.

The State Veterinarians of Maryland and Virginia were notified about the suspected case on Feb. 19. A state-imposed quarantine of the facility was implemented on Feb. 20, when two additional horses being treated at the center for unrelated problems developed fever and neurological symptoms. The hospital will not be admitting any additional patients until the quarantine has been lifted, a process which could take an estimated two to four weeks.

According to White, the decision to close the hospital was a difficult but necessary step to protect the center’s patients and the horses in the regional population.

“Although the majority of our patients had no contact with the affected horse and encountered minimal risk while at the hospital, we felt that this quarantine was essential in preventing the spread of the EHV-1 virus,” said White. “We are working closely with the State Veterinarians of Virginia and Maryland to resolve this matter as quickly and safely as possible and we will only reopen for business when we are certain that there is no chance of further infection.”

Daily updates concerning the hospital’s status are being posted on the center’s Web site at www.equinemedicalcenter.net. Clients who may have questions concerning the quarantine can call the center's toll-free hotline at 1-866-438-7235 from 9 a.m. to 5 p.m. on Monday through Friday and from 9 a.m. to noon on Saturday.

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February 22, 2007

State-imposed quarantine implemented at equine medical center due to suspected cases of Equine Herpesvirus

State officials have imposed a quarantine of the Virginia Tech Marion duPont Scott Equine Medical Center's facilities effective immediately due to the suspected infection of the neurologic form of equine herpesvirus (EHV-1) in three hospitalized horses.

No additional patients will be admitted to the hospital until further notice. Clients who may have questions or concerns regarding their horse should call the hospital’s main telephone line at (703) 771-6800. Hospital officials expect the quarantine to last anywhere from 14 to 28 days.

EHV-1, one of several strains of the equine herpesvirus, is a highly contagious disease that, although not transmissible to humans, can cause respiratory signs, abortion, peri-natal infection, encephalitis, and other complications in horses. It is spread from infected horses, which shed the virus through nasal fluids and bodily secretions, by both aerosol transmission and by direct contact with horses affected with the virus. Symptoms include fever, coughing, nasal discharge, loss of balance, urinary retention and recumbency.

“Based on the clinical signs and one positive test from the first horse with neurologic signs, we are treating this as an infection with EHV-1. We are taking extraordinary precautions and following the most stringent procedures possible in order to protect the horses in our care as well as the general equine population,” said Dr. Nat White, Jean Ellen Shehan Professor and Director of the Marion duPont Scott Equine Medical Center. “The health and safety of our patients is our first priority.”

According to White, a horse that was brought to the hospital on Feb. 7, to be treated for an unrelated emergency subsequently developed a fever and signs of nervous disease. The horse was immediately isolated in the hospital’s Biosafety Level 2 isolation unit. Initial PCR testing revealed that the horse was positive for the EHV-1 virus. “Though this test can have false positive results, we are treating this as a true infection,” said White.

In addition, hospital officials elected to impose a voluntary quarantine of patients in the area of the hospital where a risk of exposure was possible. These horses were promptly separated from the rest of the hospital’s equine population in designated isolation barns.

As of the morning of Feb. 20, two additional horses being treated at the center for unrelated problems developed fever and neurological symptoms leading state officials to deem necessary an immediate quarantine of all hospital facilities.

“The center has always followed strict biosafety procedures governing patient care, movement in and out of the isolation unit, and cleaning of stalls between each horse occupancy in order to prevent the spread of infectious diseases,” said Dr. Martin Furr, Adelaide C. Riggs Chair in Equine Medicine at the Marion duPont Scott Equine Medical Center. “However, this quarantine, which is the first that we’ve had since the center was opened in 1984, has been implemented to ensure that there is no chance of spreading the virus.”

EHV-1 is a reportable disease and the state veterinarians of Virginia and Maryland were notified on Feb. 19. The mandate to quarantine the facilities was issued by Virginia State Veterinarian’s Office on the afternoon of Feb. 20. Referring veterinarians and owners of all horses that may have been exposed to the disease have also been informed.

“I would like to emphasize that though these are not confirmed cases of EHV-1 by virus isolation or serology, we are implementing appropriate measures to prevent the spread of any contagions,” said White. “We are taking this situation very seriously and will do whatever is necessary to safeguard the well-being of our patients.”

Virginia Tech’s Marion duPont Scott Equine Medical Center is a Leesburg-based full-service equine hospital that is owned by Virginia Tech and operated as one of three campuses that comprise the Virginia-Maryland Regional College of Veterinary Medicine.