Horse News

Several cases of Potomac horse fever (PHF) have been confirmed in Bumpass, VA

July 2013

Several cases of Potomac horse fever (PHF) have been confirmed in central Virginia, prompting the Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) to release an outbreak alert. The alert was posted on the school's Facebook pageon July 13.

PHF is caused byNeorickettsia risticii, an organism found in some flukes (a wormlike parasite) that infect aquatic snails and insects (such as caddisflies, mayflies, damselflies, and dragonflies).

"Horses become infected by inadvertently ingesting infected snails, snail slime, and/or aquatic insects through grazing and drinking," the alert stated. "Due to the abnormally rainy weather, there may be an increased number of aquatic insects and snails exposing horses to this disease."

Elsewhere, the Hagyard Equine Medical Institution reported via Twitter that PHF cases were confirmed in Kentucky in May.

While there's no "absolute" way to prevent PHF, the VMRCVM suggested several methods to help reduce the risk or severity of infection:

  • Consider vaccinating against PHF. In the alert, the VMRCVM noted that while several of the horses that developed the disease had been vaccinated in the spring, the vaccine "may reduce the severity of illness in infected horses and may improve the outcome of these cases. For this reason it is recommended that horses receive a booster in areas where the disease has been reported."
  • Reduce horses' risk of exposure to aquatic insects by cleaning water sources frequently and locating buckets and troughs away from light sources that could attract insects.
  • Restrict horses' access to streams, ponds, and other standing water sources—including low-lying pasture areas—to reduce their risk of coming in contact with snails.

In a recent study on PHF survival, researchers examining the records of 50 horses diagnosed with PHF over 15 years identified clinical signs including diarrhea in 66% of horses, fever in 48%, lack of appetite in 42%, depression in 40%, and colic in 38%. Laminitis developed in 32% of the cases; 88% of these horses were affected in all four feet.

That research team learned that 76% of all PHF cases survived to discharge but those with laminitis were less likely to survive. Additionally, they found that treating affected horses with the antibiotic oxytetracycline improved survival odds twelvefold.

"Contact your veterinarian if horses develop a fever or become depressed, as early treatment increases survivability and reduces the severity of clinical signs associated with PHF," the alert read.

Click this link to go to United States Hunter Jumper Association.

Important Announcement Regarding the Use of NSAIDs - effective 4/1/2010

February 17, 2010

USHJA would like to ensure that our members are aware of the recently approved rule changes regarding drugs and medications. Beginning December 1, 2011, exhibitors may give only one NSAID, rather than two, to horses in competition due to the harmful effects overuse of these substances can have on the animal's health and well-being. (GR410.1)

PLEASE NOTE: In preparation for this change, the Federation Board of Directors approved an interim rule (GR410.4), which will be in effect from April 1, 2010 through November 30, 2011. Members will be permitted to give two NSAIDs in accordance with current rules regarding the administration of NSAIDs, provided an NSAID Declaration Form is filed with the show office prior to the horse competing.

The complete rule change reads as follows:

GR410 Equine Drugs and Medications, The Therapeutic Substance Provisions.

[Chapter 4. Drugs and Medications] Effective 4/1/10:
4. Restrictions concerning the nonsteroidal anti-inflammatory drugs are as follows:

Effective April 1, 2010 and through November 30, 2011, at which time only one of the substances listed in (a) through (f) above will be permitted, a maximum of two substances listed in (a) through (f) above are permitted to be present in the same plasma or urine sample, only if both substances are reported on a Federation NSAID Disclosure Form and filed with the competition prior to the horse competing (GR411 does not apply).

Click here to read the rule change as it appears on USEF’s website.

Under the current USEF rules, no more than two of the seven approved and quantitatively restricted NSAIDs are permitted in a horse while competing at a Federation licensed competition. The one exception to this rule is that currently phenylbutazone (bute) and flunixin (Banamine) are a forbidden combination, and are never permitted together in the horse at the time of a competition.

USEF NSAID Disclosure Form (PDF) for exhibitors.

click here for a complete listing of all rule changes from the 2010 USEF Annual Meeting.

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Calf at educational center tests positive for rabies

January 17, 2010 - 11:43am

ACCOKEEK, Md. - A six-week-old calf at a farm that does educational programs for middle and elementary school kids has tested positive for rabies.

The Maryland Department of Health and Mental Hygiene said that the calf is at the Hard Bargain Farm in Prince George's County.

Dr. Katherine Feldman, DHMH State Public Health Veterinarian, wants anyone who may have been exposed to the rabid calf to call them.

"It is critical to identify all people who may have had contact with this calf."

Feldman says if you think you were exposed to the calf since Dec. 21, 2009 to call them at 240-508-5774. The line will be staffed 24/7.

"Rabies is a deadly disease caused by a virus that attacks the nervous system. The virus is transmitted in the saliva of infected animals."

When someone is bitten or exposed to the saliva of a rabid animal, there is a series of vaccines to prevent the disease. It's a four-dose rabies vaccine over a 14-day period and a dose of rabies immunoglobulin given at the beginning of the series.

Rabies is usually found among wildlife such as raccoons, bats, skunks, and foxes, but it can be transmitted to domestic animals.

Almost 400 animals in Maryland were diagnosed with rabies last year.

To prevent your exposure to rabies:

Have your dogs, cats, ferrets, horses, sheep, cattle, or other pets vaccinated against rabies.

Keep your pet under control at all times, especially when you're traveling.

Keep your distance from wildlife and don't feed them.

Avoid sick animals or animals acting in an unusual manner.

Don't leave pet food outside or garbage cans uncovered.

Don't relocate wildlife.

Keep bats out of your house. If one gets inside, don't touch it.

You can get more information on rabies, including rabies statistics, and prevention and control of the disease on the DHMH website.

(Copyright 2010 by WTOP. All Rights Reserved.)


Should horse owners be concerned about Potomac horse fever?

By Frank Hurtig

DVM, MBA, Director, Veterinary Services, Merial

Question: I don't live in the Northeast, should I still be concerned about Potomac horse fever?

Answer: Yes. Potomac horse fever is known to occur in 43 U.S. states, three Canadian provinces, parts of South America, The Netherlands, France and India. This disease is not just a concern for Northeasterners.

Because one type of PHF test can be inaccurate, the true geographic range of the disease is not known. PHF recently was found in nontraditional areas like Wyoming and Minnesota.

The disease commonly occurs near bodies of water during spring, summer and early fall. PHF is likely transmitted when a horse ingests aquatic insects, such as caddisflies and mayflies, while grazing near a stream or river. The insects also could be attracted to a nearby stable's lights and find their way into feed and water sources.

After infection, the disease can incubate for one to three weeks before signs appear. PHF is serious, up to 30 percent of horses die from the disease. The signs can include mild depression, anorexia, diarrhea and abortion in pregnant mares. Some horses develop severe toxemia, and up to 40 percent of PHF cases founder.

No matter where you live, PHF may be prevented with vaccination. In one study, Potomavac from Merial protected 86 percent of horses from clinical disease. Potomavac is proven safe for horses as young as 3 months. Plus, it is available as a combination of Equine Potomavac + IMRAB to help protect against both PHF and rabies.

Dr. Hurtig is the director of the Merial Veterinary Services team. Before joining Merial, he worked in an equine and mixed-animal practice in Colorado. Dr. Hurtig earned his doctorate of veterinary medicine from Kansas State University and his master of business administration from the University of Pennsylvania Wharton School.



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