The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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18 TheHorse.com THE HORSE September 2016 two regions: the glandular, which covers the bottom two-thirds, and the nonglan- dular (squamous), which covers the top third of the stomach and is lined with the same tissue type that lines the esophagus. The nonglandular tissue of both species is susceptible to damage by stomach acid. In horses, acid splashes up onto the sensi- tive tissue, causing ulceration, whereas in humans acid refluxes into the terminal esophagus—which it can do because the valve leading to the stomach is not as tight as it is in horses—leading to dam- age, heartburn, and ulcers. "In gastric ulcer disease in horses, the esophageal portion (nonglandular mucosa) is most susceptible, so those ulcers we liken to gastroesophageal reflux disease (GERD)," says Andrews. "And that's probably the most common cause of heartburn in people." Treatment for equine gastric ulcer syndrome (EGUS) in horses and GERD in people are the same—administration of acid suppressants such as omeprazole (GastroGard for horses, Prilosec for people), among others. Exercise intensity and diet (e.g., high- grain) are known risk factors for horses developing gastric ulcers, so it's not surprising that this painful condition is prevalent in racehorses and sport horses. But are human athletes predisposed to get ulcers, as well? The answer is yes, says Andrews. In a 2012 study published by the American College of Sports Medicine, Waterman and Kapur found that gastrointestinal (GI) complaints—which include GERD, nausea, vomiting, gastritis, peptic ulcers, GI bleeding, or exercise-related transient abdominal pain—occurred in 30-70% of athletes studied. The type and intensity of the sport were contributing factors. Horses and people don't share as many similarities in ulcers affecting the glan- dular mucosa, which differ in appear- ance and physiology from those in the nonglandular mucosa. Instead, in horses they more closely resemble inflamma- tory bowel-like lesions in humans, says Andrews. In people, 80% of the ulcers in the glandular mucosa are related to the bacterium Helicobacter pylori and treated with antibiotics and bismuth subsalicy- late (Pepto-Bismol). Researchers have never isolated Helicobacter spp bacteria in the equine stomach, so treatment for glandular mucosal ulcers involves similar coating agents and acid suppressants, along with diet modification. The Breathing Connection Human and equine respiratory systems are also very similar in anatomy, func- tion, and fragility, says Laurent Couetil, DVM, PhD, Dipl. ACVIM, professor of large animal internal medicine at Purdue University, in Lafayette, Indiana, and president of the American College of Vet- erinary Internal Medicine, large animal medicine specialty. Over the years, research into equine respiratory conditions has confirmed that both horses and humans suffer from asthma. In horses, this condition was originally called chronic obstructive pulmonary disease (COPD), renamed re- current airway obstruction (RAO), and is now simply called equine asthma due to its similarity to human asthma in clinical signs, causes, diagnosis, and treatment. Like people, horses with asthma develop a chronic cough, mucus in the airway, and problems breathing. Both horses and people with asthma have adverse reactions to dust, mold, and other irritants in their environment. Couetil feels there's a lot to be gained for asthmatic people by studying asthma in horses. "You can look at the effect of envi- ronment, since we know people working in horse barns for a long period of time are more likely to suffer from asthma or allergic disease," he says. "You certainly can use that to see if improvement of the horse environment will also improve the people that work in that environment." Practitioners of both species can also share diagnostic methods, such as lung function tests and bronchoalveolar lavage (a "lung wash"), which involves collecting mucus and cells from the lung and view- ing them under a microscope to look for inflammatory cells and respiratory patho- gens and to determine the white blood cell profile. Unlike in humans, however, blood tests are not helpful for diagnosing equine asthma and skin allergy tests are not accurate for pinpointing associated allergies, say researchers. Treatment across species includes corticosteroids and bronchodilators, with horses wearing mask systems for medication treatments rather than using inhalers, because horses can't be trained to inhale on command. Humans and horses can each benefit from nebulizer machines, which vaporize medications Shared Science DR. ROBIN PETERSON The Equine Stomach Glandular region Nonglandular region Gastric ulcers Both human and equine athletes are predisposed to developing gastric ulcers