Experts push for greater EVA awareness, regulations - DVM
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Experts push for greater EVA awareness, regulations


What is stopping regulations from becoming more widespread among other states and other breed registries? "Apathy is the main reason," Holyoak says. The Standardbred population has lived with this virus for so many years and, despite having a high seroprevalence of infection, seldom encounters any clinical problems from the infection. The Quarter-Horse industry did virtually nothing. They said, 'Well, that's a Thoroughbred, Standardbred, eastern horse-type of problem; we're not going to deal with it. Until last year (when the outbreak occurred)."

"Though I've been working with EVA for almost 24 years, and a colleague of mine, the late professor William McCollum, (did so) for over 50 years," says Timoney, "it is amazing that despite the amount of information you disseminate, it just seems as if very little of it registers with the actual breeder, owner or the veterinarian. Nevertheless, it is important to persevere. No matter how much information is out there, there never is enough.

"I also think it most important to try to make sure that what's known scientifically about the virus/disease is reduced to terms and language comprehensible to the owner, breeder and, truthfully, also to many practicing members of the veterinary profession. I would have to say that on occasion I've encountered more obduracy and lack of comprehension of this disease from veterinarians than I have from owners or breeders."

Tightening the reins

In order to properly control and possibly eradicate it, "it would be better if people were more open about EVA," Sheerin says.

"If everyone got together it could be eliminated by vaccination, but there's been resistance to that."

"Unfortunately the United States is the only major horse-breeding, racing, performance country in the world that has zero post-entry testing requirements for this infection," Timoney says. "What we're advocating is for a proposed rule for EVA to be developed by the USDA. When previously solicited, the majority of the public indicated that they did not want restriction on the ability to import carrier stallions or virus-infective semen, merely that — if positive for EVA — these animals be identified at point of importation. The goal would be to ensure that the owner, breeder or distributor (of semen) would know and could advise their respective clients of the risks associated with specific importations. There are certain precautions and safeguards that are necessary to take when using infective semen in a nave mare.

"We're not striving to bar the entry of either the live animal — i.e., the carrier stallion — or infective semen, but rather to continue to allow these to be imported, subject to identification of carrier stallions/infective semen."

Equine practitioners involved with the AI industry are concerned with this, especially if working with those breeds that have a higher seropositive rate for EVA.

Those at a higher risk of having stallions that are persistently infected are Warmblood horses, especially out of Europe.

Besides paying attention to seropositive stallions and regulations, diagnostic laboratories must meet competency qualifications to test for the infection, the experts say.

Mare owners and veterinarians, too, need to be aware of the potential risk involved with breeding, and make sure stallions have been EVA-screened, they add.

"In the ideal world, it would be nice to vaccinate (all animals) and get rid of the disease. Maybe 'get rid of it' is too optimistic, but I think we could control it a lot better than it is currently being controlled, just by vaccination," Sheerin says.

"If there were awareness, attention and vaccination, we'd eliminate the disease," adds Holyoak, whose doctoral work dealt with whether pre-or peri-pubertal colts could become persistently infected with EVA. "Once we had that information, it became clear that if we could vaccinate colts prior to any testosterone-dependent tissue development, we would effectively eliminate the chance of them becoming persistently infected. It's been in the literature and Timoney has been preaching it," Holyoak says.


Source: DVM360 MAGAZINE,
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