The latest equine immune system research in horses young and old.

The immune system is an amazing concept in both man and beast. It allows us to survive in a very complex world filled with harmful bacteria and viruses that can use our bodies for nourishment and reproduce within us. The immune system protects us from those organisms both by limiting their entrance into our bodies and helping rapidly eliminate the ones that manage to make it past those initial defenses (e.g., the skin, hairs within the nasal passages). Just as in humans, if a horse’s immune system isn’t functioning properly, he doesn’t have a good prognosis for a long or healthy life.

There are several components to a horse’s immune system. The structures or molecules that induce an immune reaction are called antigens, and these indicate to the immune system that a foreign and potentially dangerous material (such as a pathogenic [disease-causing] bacteria or virus) is present. The immune system then produces antibodies (special infection-fighting proteins) to destroy the invading organism. (Read a more detailed rundown of how the horse’s immune system functions on page 23.)

Welfare and Research

Researchers throughout the world are studying the equine immune system and particularly, how it interacts with infectious diseases such as equine herpesvirus, influenza, and Streptococcus equi (the bacterium that causes strangles). D. Paul Lunn, BVSc, MS, PhD, MRCVS, Dipl. ACVIM, professor and head of the department of clinical sciences at Colorado State University’s (CSU’s) James