Because of the outbreak, the NYRA isn't taking any chances. "The New York State Racing Association has put in a directive requiring veterinarians to show that horses have had no fevers for the last three weeks," said Ed Dubovi, associate professor of virology and director of the virology diagnostic laboratory at the Animal Health Diagnostic Center at Cornell. He says that Cornell only administers testing and does not set the rules for monitoring infections.
Dubovi said that in the last four to five years, there have been more reports of the severe neurological disorder associated with equine herpes. "It appears we are seeing it with more frequency and in a larger number of horses," he said.
Previous studies on horses have found the inactivated vaccines are not very effective in lowering equine virus levels in the blood or preventing abortions caused by the virus. "Based on recent reports and our preliminary findings, many inactivated vaccines, especially when given too often, don't appear to do much good," said Osterrieder.