Equine immunodeficiencies can be challenging for veterinarians to diagnose, and even more difficult—or impossible—to manage. | Photo: Anne M. Eberhardt/The Horse

At the 2013 American College of Veterinary Internal Medicine Forum, Sandra Taylor, DVM, PhD, Dipl. ACVIM, assistant professor of large animal medicine at Purdue University’s College of Veterinary Medicine, reviewed equine immunodeficiencies and described recent research that’s helping veterinarians better understand these difficult disorders.

Taylor said equine immunodeficiencies can either be primary (meaning they have a genetic origin) or secondary (meaning they’re acquired after the horse is born), and they’re “characterized by an incomplete or absent immune system that allows organisms to invade the host and cause disease.”

She noted that while rare, immunodeficiencies—mainly primary ones—present veterinarians with a diagnostic challenge because affected horses typically present with nonspecific clinical signs and recurrent infections