Delaware Farms Quarantined as EHV Monitoring Continues

Six farms in the state of Delaware are in quarantine until February 7 as state officials monitor horses for clinical signs of Equine Herpes Virus, Type 1 (EHV-1).
Most of the farms are located in Kent County.

While several horses on the farms tested positive for EHV, the investigators are looking for horses showing signs of elevated temperature and other signs of the disease.

An update from the state dated 31 January clarifies: "Merely finding the neuropathogenic form of EHV-1 on a nasal swab does not constitute a 'case'. A case is defined as clinically infected (neurologic disease) with positive EHV-1 PCR test results. The original 21-day quarantine was a result of the index case showing signs of disease (down, unable to get up, requiring euthanasia) and a positive nasal swab test result. Since the original index case, there have been no new cases, hence the original 21-day quarantine will stand."

Anne Fitzgerald, Chief of Community Relations for the Delaware Department of Agriculture confirmed today that no additional cases or quarantines have been added to the state's list.

For foreign readers: Delaware is a small state on the east coast of the United States near the cities of Philadelphia, Baltimore, and Washington. Both Thoroughbred and Standardbred racing are active in the state, along with show and pleasure horses of all types. Delaware is in the middle of the north-south corridor of horse transport. Horses ship into, out of, and through Delaware constantly.

Oklahoma State Spearheads New EHV Research

Dr. Lara Maxwell, Assistant Professor of Physiological Sciences at the Oklahoma State University Center for Veterinary Health Sciences, has received a grant from Grayson Jockey Club Foundation to study the efficacy of an antiviral drug to fight Equine Herpes Virus Type I (EHV-1).

The study will revolve around the testing of an antiviral drug called valacyclovir. Laboratory and live animal data suggest that this drug will be effective if given in the same doses that Maxwell’s team will be administering.

“We will test the drug to see whether it protects horses from EHV-1,” says Dr. Maxwell. “This is a two year study, but we hope to have preliminary results by the 2008 meeting of the American College of Veterinary Internal Medicine (ACVIM). If the drug is effective, this project will have far reaching consequences for horse owners and the horse industry.”

“This virus can affect horses of any age, but causes different signs of disease in foals, pregnant mares, and in other adult horses,” explains Dr. Maxwell. “Recent outbreaks of EHV-1 at farms and racetracks around the U.S. have caused severe neurological disease in adult, vaccinated horses. Therefore, current vaccines don’t seem to fully protect these horses from the devastating affects of EHV-1.”

Dr. Maxwell will be collaborating with various researchers from the Veterinary Center and will also team up with colleagues Drs. Brad Bentz at the Hagyard Equine Medical Institute in Lexington, Kentucky, and George Allen, at the University of Kentucky.

(this report is edited from an OSU press release)

Recent EHV in South Carolina Clarified

The Aiken Standard, a newspaper in horsey Aiken, South Carolina, has a report today that clarifies reports of an "outbreak" of Equine Herpes virus (EHV), Type 1, in Aiken.

Apparently only one horse is affected and is being isolated and treated.

Among other things, the article says:

"There isn't an outbreak of equine herpes in Aiken County," said Dr. Jamie Carter of Southern Equine Services, who is treating the horse.

"The horse is being treated and recovering very nicely. It was a voluntary quarantine at the farm, and no other horses on the farm have shown any symptoms."

The article goes on to quote Dr. Nicola Pusterla of the University of California at Davis, in an article in EQUUS Magazine. It does not mention what the origin of the horse's infection was or if the horse is a show or race horse that may have been off the farm recently. Many horses test positive for the disease without showing symptoms; symptoms (fever, nasal discharge, etc.) may erupt after a stressful incident.

EHV-1, sometimes called "rhino" or just "flu" in conversation, is a highly contagious viral disease. A powerful strain causing neurological symptoms is a great cause for concern when new cases are found.

The disease is spread primarily by horse-to-horse contact and by contamination, ckets, tack or almost any equipment or physical structure that can become infected when a horse sneezes.
Horse owners should know that state regulations regarding notification about contagious horse diseases vary from state to state and between diseases. In most states, the barn next door to yours could be experiencing an outbreak, but you wouldn't know it unless the information was publicized. In other states, cases must be reported to the state veterinarian's office.

EQUINE HERPES VIRUS-1 IN VIRGINIA: Update

The following information is provided by the Commonwealth of Virginia:

February 23, 2007

The Virginia Department of Agriculture and Consumer Services (VDACS) is taking precautionary measures and quarantining additional farms in Virginia due to an outbreak of Equine Herpes Virus-1 (EHV-1). Previously, VDACS quarantined the Marion duPont Scott Equine Medical Center (EMC) in Leesburg and one farm in Loudoun County.

In the hours following discovery of a horse possibly infected with EHV-1 at the EMC, both Virginia and Maryland learned of additional horses that may have had contact with that animal. Both states are conducting investigations and doing trace-backs on at-risk horses. Virginia is placing more quarantines today.

This represents a total of approximately 175 horses under quarantine, only three of which have shown neurological signs of EHV-1. One of those horses resides in Fauquier County and two in Loudoun County.

EHV-1 in a highly contagious disease that presents no known health threat to humans, but humans can spread it from farm to farm on their clothing, shoes, tires, or equipment. To enhance bio-security, VDACS has cancelled the Casanova Hunt Club Point-to-Point and the Casanova Hunter Pace events this weekend because of their proximity to a quarantined premises.

Dr. Richard Wilkes, Virginia State Veterinarian, said, “We are being very conservative in our approach and are quarantining farms that have horses on the premises that were at the equine center during the possible contagious period. The quarantines are precautionary measures and do not mean there are sick horses on the premises. No horse on a Virginia premises outside the equine center has been confirmed to have EHV-1, but we have tested some horses on contact farms that have fevers and no other signs and one horse that has neurological signs. We expect to receive test results early next week. This aggressive approach is to try and contain any possible exposure while we assess the risk that this event holds for our horse industry. Virginia horse-owners need to understand that we are being proactive and pre-emptive at this time to protect our state’s horse industry. We have cancelled a couple of equine events to add another measure of protection.”

Wilkes added, “We are working with faculty at the Virginia-Maryland Regional College of Veterinary Medicine at their Blacksburg and Marion duPont Scott facilities, the Virginia Association of Equine Practitioners, USDA, and the Maryland Department of Agriculture to be sure that we take responsible, effective action to control EHV-1.”

Wilkes encourages activity planners to consider upcoming events in Northern Virginia carefully and to postpone all non-essential ones to minimize the occasions where horses co-mingle. The mixing and mingling of horses has the potential to compromise bio-security as they move from area to area.

Quarantines will restrict movement on and off the affected facilities. In addition, veterinarians are urging horse owners to observe strict hygiene control procedures to avoid spreading the disease in the environment. This includes a thorough cleaning and disinfecting routine using a proven disinfectant/cleaner.

Editor's Note: An informational meeting is being held at Morven Park today (2/24) for local veterinarians. An informational meeting for the horse community will be held at the Best Western in Leesburg from 7 to 9 p.m. Monday, February 26, according to an article in the Leesburg Times.

EHV-1 Quarantine Imposed at Marion duPont Scott Equine Medical Center in Virginia

Virginia state officials have imposed a quarantine of the Marion duPont Scott Equine Medical Center's facilities at Morven Park in Leesburg, Virginia, effective today (Tuesday, February 20). Officials there 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. Hospital officials expect the quarantine to last anywhere from 14 to 28 days.

"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 Wednesday, February 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 Tuesday, February 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 Monday, February 19. The mandate to quarantine the facilities was issued by Virginia State Veterinarian's Office on the afternoon of Tuesday, February 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."

In 2002, four horses with EHV-1 in the nearby town of Middleburg were euthanized.

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.

More information is available in an article in the region's newspaper, Loudoun (VA) Times Mirror.

Photo of Dr. Nat White provided by Marion duPont Scott Equine Center.

© 2006-2007 The Jurga Report: Horse Health Headlines. All rights reserved.
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EHV-1 Surfaces Again at Racetracks in California

Dr. Rick Arthur, equine medical director for the California Horse Racing Board (CHRB), announced yesterday that two barns are under quarantine at Los Alamitos Race Course following the deaths of two horses from the Equine Herpes Virus (EHV-1). One was a stable pony and the other a racehorse. Lab results are pending on other suspected cases.

Elsewhere in California, a mare at Golden Gate Fields near San Francisco aborted a fetus, which subsequently tested positive for EHV-1, although the mare tested negative according to the CHRB. Biosecurity measures are in place at that track.