Spring’s slow arrival has brought many things. Disappearing snow, a hint of green in the grass… and a greater risk of disease outbreaks in horses. Outbreaks can occur at any time of year but we often start to see certain infectious diseases ramp up as horses start moving around more at the start of training, racing and showing seasons.

A tentative diagnosis equine herpesvirus I (EHV-1) neurological disease in a horse has resulted in a precautionary quarantine of a barn at Aqueduct racetrack in New York. This virus is a concern because of the potential for serious disease (e.g. the affected horse died) and the potential for large outbreaks. However, concern needs to be tempered by awareness that this virus is widespread in the horse population and that single, sporadic infections are more common than outbreaks.

At Aqueduct, horses in the barn in which the affected horse was housed are not permitted to race, and may only train after the general horse population is off the track. Rectal temperatures of horses from that barn are being checked twice a day to help detect any new cases as soon as possible. Usually, this type of outbreak response goes on for 21-28 days after the last identified case, but the planned time frame hasn’t been stated here.

Too often, we see one of two things happen when EHV-1 is identified. Traditionally, little was done in the hope that nothing bad would happen. More recently, the pendulum has swung the other direction and people often completely freak out over it, panicking and implementing measures that are over the top.

Like most things, a happy medium is needed, with enough attention (and common sense practices) to reduce the risk of further cases, while no causing undue hardship to those affected. It’s not always an easy balance to find. As someone who is frequently involved in these situations, it’s tough to figure out where to draw that line, especially when you have multiple different agendas, perceptions and degrees of risk tolerance. Taking a draconian approach (lock all the horses in the barn until further notice) is the easy way out, but it rarely makes sense. Being more balanced and less restrictive creates some risk for people making those decisions (because if something bad happens, they’re probably going to be blamed) but the easy-way-out is rarely the best-way-out.

The response at Aqueduct seems to be well balanced.

  • They’ve identified a potential problem.
  • They’re trying to determine if there are more cases (although I’d take temperatures of all horses on the track, not just that barn. You need to know if it’s escaped from the index barn.)
  • They’re communicating.
  • They are taking reasonable measures with the highest risk group (horses from the affected barn).
  • They’re not taking the easy, knee-jerk response of totally restricting horses in that barn, rather they are using common sense practices to limit the risk of further exposure should any other horses in the barn be affected.

Most often, these incidents end up being single cases. However, by the time you realize something is going on, it’s possible that multiple horses have already been infected and are getting ready to become sick and/or be able to transmit the virus further. A short period of relatively aggressive but reasonable precautions is usually the key in outbreak management, and hopefully nothing more will come from this.

The location of this outbreak can be seen on the Worms & Germs Map at http://www.wormsandgermsmap.com