Equine Researchers Outline Steps Being Taken on Fetal/Foal Loss Syndrome

By Kimberly S. Graetz
Thoroughbred industry leaders, veterinarians, researchers, and farm managers met with the media at the Gluck Equine Research Center in Lexington, Ky., for a press briefing on the current fetal/foal loss syndromes occurring in the state. While there are no answers as to why so many mares are aborting in near-term or having stillborns in late term, there are defined paths being taken that everyone involved hopes will lead to the cause.

One of the main thrusts of the meeting was to call on all farms that receive a survey from the Kentucky Thoroughbred Farm Managers Club and researchers at the Gluck Center to return the information promptly. Only through this broad gathering of information can the facts of this situation be revealed.

"We need to identify factors that could be contributing to this problem," said Dr. David Powell, an experienced epidemiologist from the Gluck Center. "This has happened quickly over a wide extent of farms, but there are a number of farms that have not experienced problems. It will help us to get information from all farms."

Preliminary Information
Lenn R. Harrison, VMD, Dipl. ACVP, Director of the Livestock Disease Diagnostic Center in Lexington, gave a report on what his staff has seen thus far at the diagnostic lab. He said since April 28, 2001, the Diagnostic Center has received 318 aborted/stillborn equine fetuses/foals for diagnostic testing and evaluation. Harrison reported that during the same time period in 2000, only 46 aborted/stillborn equine fetuses/foals were received. "This represents a nearly 700% increase in submissions of equine fetuses/stillborn foals for this timeframe," he said.

Most of the fetuses were from Thoroughbreds, said Harrison, although there were numerous other breeds represented. This points to the fact that whatever the problem, it affects broodmares, not just Thoroughbreds.

Harrison also noted that 25 fetuses from 50 to 80 days of age have been submitted for testing. "We don't usually expect to receive early fetal losses because they usually are not found," he explained. "Receiving as many as we have is remarkable and give us samples to test." Each submission will be handled independently and will have a case report written up by the professional and technical staff "who are specialists in essential disciplines in veterinary diagnostic laboratory medicine. Specialists involved are pathologists, bacteriologists, serologists, toxicologists, and virologists."

The testing has revealed that there are some pulmonary changes in the lungs that appear to be a mild pneumonia. "This has been the only remarkable observation made on gross examination" of the submitted foals, he said.

Toxicological examinations have shown that the samples are negative for nitrates and nitrites. Tests have been normal for levels of copper, iron, selenium, and zinc in mare sera.

All samples have been negative for equine herpesvirus 1 and 4, equine arteritis virus, and adenovirus. "Attempts to isolate an 'unknown' virus are in progress, but we don't expect there is one present," added Harrison. None of the samples have been positive for leptospirosis.

Aerobic bacteriologic cultures of internal organs of 154 foals and seven fetuses have resulted in positives for the following: Actinobacillus equuli in 45; Streptococcus spp in 75; A. equuli and Streptococcus in 2; Streptococcus zooepidemicus in 2; Staphylococcus sp in 1; Coliforms in 3

Harrison did not think any of these bacteriologic results were significant to the current situation.

Sequence of Epidemiologic Events
Powell and Dr. Roberta Dwyer, also an epidemiologist at the Gluck Center, were first alerted to the situation on May 2. They visited two farms experiencing problems on that date. The following day, a meeting was called with veterinarians and research colleagues at the university to help identify the problem and determine what samples needed to be taken to begin an investigation.

The number of phone calls from veterinarians and concerned owners increased "significantly" on Friday, May 4, and by May 5, Kentucky Derby day, Powell and Dwyer knew they needed to get a handle on the incidence. On Sunday, May 6, an informational fax was sent to area veterinarians with what limited information was available.

A questionnaire was sent to area Thoroughbred farms on Monday, May 7, through the Kentucky Thoroughbred Farm Managers Club. "We hope the results will be available by the end of Wednesday (May 8)," said Powell. "That should give us an accurate picture of what is happening. We can identify farms with and without problems to help identify factors that are contributing to the situation."

He added that there has been tremendous cooperation from all the farms in getting information.