http://www.thoroughbredtimes.com/todaysnews/newsview.asp?recno=33993&subsec=1

Posted: 5/30/2003 12:48:00 PM ET

West Nile vaccine could be causing equine abortions

Midwestern horse owners who have administered a vaccine for West Nile virus to pregnant mares have reported to the United States Department of Agriculture an increase in aborted and deformed foals.

The owners have formed an activist group, the Lost Foals Group, and they successfully lobbied Fort Dodge Animal Health, the division of Wyeth that developed the vaccine, to change information on its Web site to reflect the concerns of the horse owners.

Fort Dodge now relates that "a low number of undiagnosed abortions have been reported from the field following use. These reports appear to be associated with individual animal responses from the vaccine or due to stress, which may occur with any vaccine administered to pregnant animals."

The USDA has been fielding complaints from the horse owners, primarily Quarter horse breeders. One such report included information that a mare had produced a colt with no front legs or shoulders after receiving two doses of the vaccine.

"It’s a real heartbreaker to have to put a foal to sleep like that," USDA biologic specialist and veterinarian Charles McDaniel told the Denver Post. "They can’t even get up to nurse."

Despite the concerns, it is unclear whether the vaccine is related to the aborted and deformed foals.

"I don’t want to say it is vaccine related at this point in time," McDaniel said. "I’m not going to say it isn’t, either. We just don’t know."

John Tuttle, D.V.M., Fort Dodge manager of professional services, said that his company wants to assess and address the situation.

"We started getting the calls from the field," Tuttle said. "We didn’t want to have inaccurate information."

Tuttle said that the company has investigated each problem pregnancy report and found that spontaneous abortions occurred at a rate of 3.3 for every 1-million doses of the vaccine sold. That equates to about 24 cases nationwide and does not point to a large trend.

McDaniel said he is not sure how the USDA would pursue the reports. The agency could launch a formal investigation, which would force Fort Dodge to stop selling the vaccine and recall doses already on the market.

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