A question has been raised whether the increased number of West Nile virus (WNV) cases in Kentucky in late summer and fall 2002 contributed to a rise in fall abortions. A retrospective study by the University of Kentucky's Livestock Disease and Diagnostic Center (LDDC), from July of 2002 through early 2003, looked at 400 equine abortions for evidence of WNV. Their findings were "surprising," said LDDC head Lenn Harrison, VMD. Of the 400 examined, 35 (about 8.8%) had evidence of WNV identified on polymerase chain reaction testing. This is the same test the laboratory uses to check for WNV in birds.

West Nile virus has not previously been associated with abortion, and researchers are not saying that is the case now. They have no evidence at this time that WNV caused the abortions; they are only saying that there was evidence of the virus in the aborted fetuses. The virus has not been isolated in the fetuses at this time.

Further testing and information gathering is ongoing to determine the relationship between WNV and abortion.

Florida Report

Maureen Long, DVM, PhD, assistant professor of large animal veterinary medicine at the University of Florida (UF), is researching clinical WNV infection in horses. So far, very informal inquiries have not given evidence of increased abortions in Florida. But she says that the Florida Thoroughbred industry, pleasure horse breeding groups, and UF are looking at breed registry information and fetal abortion submissions. Long will also work with Kentucky researchers to follow some farms affected by WNV in terms of reproductive losses.

Leroy Coffman, DVM, director of the Division of Animal Industry at the Florida Department of Agriculture and
Consumer Services, said they have not found any correlation of abortions to WNV infection. "However, there has been proven evidence of human fetal infection in individuals affected during pregnancy. The true impacts are not clear. All impacts are relative to the level of infection. With all the virus circulating this past year, especially in states like Kentucky, I am not surprised that they have identified WNV in fetal abortions. At this time we have no ability to determine any direct impact WNV infection has on abortions. In the absence of 'abortion storms' coincidental with WNV activity, I would have to say the impact is present, negligible, and directly related to general loss of condition and health due to WNV challenge."--Stephanie L. Church and Kimberly S. Herbert

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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