Scientists in Kentucky say it is too soon to tell whether West Nile virus (WNV) has been causing equine abortions. But they have found enough evidence to make them want to explore the possibility that the disease can play a role in fetal loss.
Polymerase chain reaction testing has revealed the presence of WNV in 35 fetuses submitted to the University of Kentucky's Livestock Disease Diagnostic Center (LDDC) for examination since last July. According to LDDC's director, Dr. Lenn Harrison, the horse industry should not be unduly alarmed because the total represents less than 10% of the approximately 400 fetuses submitted.
The LDDC plans to take a closer look at information gathered from the aborted fetuses that tested positive for WNV. In addition, Harrison and his staff hope to obtain more information about their mares, including the results of blood work and whether or not they were vaccinated against WNV. The scientists also plan to look for evidence of WNV in newborn foals in Kentucky and to test other mares on the same farms where the fetuses were aborted
LDDC scientists started testing aborted equine fetuses for WNV last year because of the high incidence of the disease in Kentucky, Harrison said. He added that this is the first time WNV has been found in equine fetal tissue. There is some evidence in humans that WNV can cause damage to a fetus.
"I have heard of one human case where the mother was infected with West Nile virus and the fetus was born with neurologic problems," said Harrison during a press conference Tuesday at the University of Kentucky. "There was very good evidence to support the fact that the fetus was affected. We don't know if West Nile virus is significant or not in equine abortions, but we're working toward the goal of finding out that information."