EVA Vaccination Snafu Blocks Top European Horse from Running in Japan

Dylan Thomas, who was recently named Cartier Horse of the Year and top older horse in Europe, is no longer a contender for the Nov. 25 Japan Cup due to not testing negative for equine viral arteritis (EVA).

A series of examinations conducted as a part of the regular quarantine import procedure at Shiroi Quarantine Station revealed the non-negative results. Consequently, the 4-year-old Irish-bred son of Danehill was not approved to enter into Japan as a part of the sanitation provision established between Ireland and Japan. In its history of horse racing, Japan has so far been free from the disease.

In a statement released Nov. 20, trainer Aidan O'Brien said Dylan Thomas was vaccinated for EVA prior to the Oct. 27 Breeders' Cup Classic at Monmouth Park. Although not confirmed, it is believed that vaccination might be responsible for the horse's elevated antibody level.

"This is a standard procedure for all stallions going to stud, as it is in the best interest of the stallion and mare owner," O'Brien said. "Many of our stallions in the past have entered Japan with the EVA vaccination before entering stud."

Dylan Thomas's case does not have any effect on other overseas horses in the quarantine facility, and the horses in quarantine at Shiroi are on schedule to move to Tokyo Racecourse Nov. 20.

The sanitation provision between Ireland and Japan for the equine viral arteritis requires the horse, prior to departure from Japan, to be stabled at an EVA-free facility for 60 days. It must not show irregular clinical signs and must produce a negative antibody examination result within 30 days. During quarantine in Japan, the horse must be free from clinical signs and approved negative upon antibody examination.

According to O'Brien, the Hong Kong Jockey Club has extended an invitation for Dylan Thomas to run in the Hong Kong Vase at Sha Tin Racecourse Dec. 9. "We hope that the Japanese Racing Association will release him in time to run," O'Brien said.

Dylan Thomas is scheduled to stand the 2008 breeding season at John Magnier and partners' Coolmore Stud in Ireland. The season officially starts in February.

Clinical signs associated with EVA are fever, respiratory illness, ocular inflammation, edema (fluid swelling) of the legs, prepuce, and scrotum, pneumonia or pneumonia enteritis in foals, and abortion. The virus can be spread through semen from infected stallions, infected respiratory secretions, or indirectly through shared breeding shed equipment or tack.

(Originally published at BloodHorse.com.)

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