Oregon State University researchers have reported a link between vesiviruses, which can affect a wide variety of mammals, and mare reproductive loss syndrome (MRLS). University of Kentucky researchers studying MRLS are concerned the results of the study could be misconstrued and say the link of vesiviruses to MRLS is premature.

The Oregon researchers reported a "significant association" between finding antibodies in blood samples for vesivirus and abortion in mares. (Read Oregon's summary of the experiments here: www.TheHorse.com/ViewArticle.aspx?ID=7141.)

Bruce Webb, PhD, a University of Kentucky entomologist and MRLS researcher, provided many of the samples used in the Oregon study. According to Webb, the OSU report describes a correlation, not a cause.

University of Kentucky MRLS studies have shown little evidence of a virus being the cause of MRLS, such as a fever in affected mares or evidence of direct transmission of the disease between mares. "There is no direct evidence that vesiviruses have caused a single case of MRLS," Webb said.

"In my view, the weight of the evidence, both experimental and practical, argues against vesiviruses having any role in MRLS," Webb said. "So, I think that I speak for all of us (at the University of Kentucky) in saying that we are very comfortable with the results of our work and the recommendations that we have in place. Specifically, if farm managers and horse owners control exposure of pregnant mares to Eastern tent caterpillars, it is an effective means of preventing MRLS."

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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