Pacific Crest Sporthorse Hot Topics


Why a Coggins’s test? The Latest on Equine Infectious Anemia

            There has been a lot of discussion about Coggin’s test requirements lately, primarily because the rules are changing.  This blood test identifies antibodies against the virus that causes Equine Infectious Anemia (EIA), a severe disease that has no available vaccination, treatment or cure. Once infected, a horse will carry the virus for life. The Coggin’s test, developed by Larry Coggins in the 1970’s, identifies antibodies against the EIA virus in an infected horse’s blood.

            The disease was first identified in France in 1843, and diagnosed in North America in 1888. It is a classic blood-borne disease that can be easily transmitted from horse to horse by biting insects.  Most commonly, horse or deer flies will bite an infected horse, then carry the virus in their mouth parts to another horse when their feeding is interrupted by resistance such as a strong skin twitch or swished tail by the first horse.
When first infected with the virus, a horse may show no signs other than an elevated temperature in the first 24 hours, yet death is common within two to three weeks. One-fifth of a teaspoon of blood from an acutely infected horse can contain enough virus to infect a million other horses. If an infected horse survives the acute infection, EIA can become a chronic disease with intermittent fevers ranging from 105 to 108 degrees farenheit, weight loss, edema in the legs or belly and anemia.  The same one-fifth teaspoon of blood from one of these chronically infected horses carries enough virus to infect 10,000 other horses.  Finally, perhaps the most frightening characteristic of this virus is that a horse can become an inapparent carrier—meaning they harbor the virus but show no signs of the disease.  Although the chance of a horsefly picking up the virus from an inapparent carrier is slim (only one horsefly out of 6 million is likely to transmit the virus), it’s still possible.  And an inapparent carrier can develop chronic, or even acute disease in response to stress.

             In the 1980’s, health officials worked very hard to eradicate EIA from horse populations in the United States, by establishing requirements for Coggin’s testing of horses prior to transport across state lines, and demanding either euthanasia or stringent quarantine of horses with a positive test that identified them as carriers. Euthanasia is encouraged to reduce risk of spread.  When possible, strict lifelong quarantine in a completely screened in stall more than 200 yards from all other animals is required. These testing regulations have continued to the present day, although they are constantly being adjusted by state agencies—primarily in response to levels of risk.

             Until recently, the Oregon Department of Agriculture had a Memorandum of Understanding with both the Washington State Department of Agriculture and the Idaho Department of Agriculture that allowed horses to travel between Oregon, Washington and Idaho without requiring proof of a negative Coggin’s test.  As of February of this year, that Memorandum has been terminated and from this point forward Oregon will require a negative Coggin’s test within six months for all horses crossing the border into the state.

           Why the change? The state veterinarian reports that “ten EIA positive horses in Washington and four in Oregon were detected in 2015 and early 2016. Additionally, one EIA positive horse was detected in Idaho in 2016. Because of these recent EIA positive detections ODA believes it is in the best interest of our equine industry that the EIA testing waiver be annulled and that EIA testing be resumed for interstate movement.” It is reported that as many as 500 new cases of EIA are still identified every year in the United States.

          So how much should you worry?  Even with these reports of positive tests, the chances of your horse becoming infected with the EIA virus are extremely slim.  That said, it does make sense to take testing requirements seriously and follow all the rules when transporting your horse across state lines.  These rules are in place to help maintain control of this frightening disease and protect not only you and your horses, but horse populations in general.


If you have any questions, please don’t hesitate to call our office at 503-632-6336 for more information.



Barb Crabbe DVM
Jennifer Posey DVM
Lindsey Moneta  DVM


Could your horse have Ulcers?


Could your horse have ulcers?  Estimates say between 60-90% of adult horses do have gastric ulcers, with performance horses being at higher risk.  In fact, a recent study showed that horses could develop ulcers simply from being hauled to a new location for a period of several days.  Ulcers can cause a wide variety of signs, ranging from colic symptoms, weight loss and a general decline in overall condition to a sore back, girthiness or simply poor performance.

            As a horse owner, you may be wondering whether you should administer anti-ulcer medications to your horse…and if you do what should they be?  Studies clearly show that GastroGard omeprazole paste is the most effective medication for treating gastric ulcers—but it is expensive.  Many other medications are marketed that may cost less—but are also less effective. In fact, some don’t work at all.  Clearly, if your horse does have gastric ulcers you want to treat him right.  Given this, it just makes sense to accurately diagnose your horse’s condition.

            An accurate diagnosis for stomach ulcers is easy to make. By passing a long fiber optic instrument called an endoscope through your horse’s nose and into his stomach we can directly visualize the stomach lining and see ulcers if they are present.  The procedure is quick and easy.  It only requires that your horse be fasted overnight and administered a light dose of sedation.   With the results of this examination we can answer your questions and help you formulate an effective treatment and management plan to keep your horse performing at his best.

"The Most Up-To-Date Equine Medical Reference Available"

This guide for horse owners, veterinarians, and students of veterinary medicine covers every critical aspect of equine health management.

Written by our own Dr. Crabbe

"Items in the News"

Do non-steroidal anti-inflammatory drugs (NSAIDS) cause stomach ulcers? Learn the truth

We've all been there.  "Champ" has an injured leg, and you've been instructed to give him bute for the next several days.   You want to do what's right for his leg, but you're concerned—he's a sensitive horse, and you've heard that bute can cause stomach ulcers.  Is this true?  Should he get anti-ulcer medications too?  

L.C. Fennell and R.P. Franklin have addressed this very issue in an article in the December 2009 Equine Veterinary Journal, titled "Evidence-based Clinical Question: Do nonsteroidal anti-inflammatory drugs administered at therapeutic dosages induce gastric ulcers in horses?"  This article reviews the frequency and appearance of stomach ulcers in horses, and whether NSAIDS like bute and Banamine put your horse at risk.

Fennell and Franklin review multiple studies that evaluate NSAID use and stomach ulceration in performance horses.    All of these studies had the same conclusion: there was no connection between NSAID use and stomach ulcers when appropriate therapeutic dosages were used.   Therefore, there is no reason to give your horse anti-ulcer medications when he's being dosed appropriately with an NSAID.

What can we take from this article?  Go ahead and follow our instructions regarding Champ's bute.   Be vigilant in following directions—ask if you have any questions!  While NSAIDs are unlikely to cause stomach ulcers at therapeutic dosages, they are harmful if your horse is over-dosed.  Lastly, save your money and don't give anti-ulcer medications when they're not needed.  If you think your horse may have ulcers, discuss endoscopy with your veterinarian.