Disease spreads invisibly, often thanks to horses shedding disease but not showing signs. In equine disease outbreaks a veterinarian often wears the hats of sleuth, adviser, and sometimes unpopular gatekeeper/rule enforcer.

At the 2016 American Association of Equine Practitioners Convention, held Dec. 3-7 in Orlando, Florida, Peter Morresey, BVSc, Dipl. ACT, Dipl. ACVIM, of Rood & Riddle Equine Hospital in Lexington, Kentucky, described how to investigate and control infectious respiratory disease outbreaks.

Leading causes of these outbreaks in equine populations include equine herpesvirus-1 and -4 and equine influenza virus, as well as equine arteritis virus and strangles (Streptococcus equi subspecies equi)