The bacterium Salmonella enterica can spread quickly between horses on a farm or in a hospital setting, causing significant financial and even equine losses. So during the 2018 British Equine Veterinary Association Congress, held Sept. 12-15 in Birmingham, U.K., Nathan Slovis, DVM, Dipl. ACVIM, CHT, of Hagyard Equine Medical Institute, in Lexington, Kentucky, described how to manage these cases for the best outcomes.

The hallmark sign of this infectious and zoonotic (can transfer between humans and animals) disease is profuse diarrhea. It typically spreads via the fecal-oral route but can also be shed by subclinical horses (those carrying the bacteria without showing signs) after stressful situations such as trailering or showing. Horses at most risk include neonates, animals on antibiotics, and stressed animals, Slovis said.

Along with the obvious concern of sick and contagious horses, the impact of a Salmonella outbreak on a veterinary clinic is substantial. Slovis said an outbreak cost one hospital close to $300,000 in expenses related to disinfecting the facility as well as lost income as a result of closures and associated legal fees. This is why it’s particularly important to identify and manage subclinical horses appropriately.

Slovis said he and his colleagues routinely test any horse admitted to their hospital. This biosecurity surveillance allows for early detection of clinical and subclinical horses, he said.

If you do detect a subclinically affected horse, however, “it’s not the end of the world,” he said. In fact, with a few common-sense biosecurity steps, the horse can return to its farm while being treated.

Before sending an affected horse home, Slovis said he instructs the owner or caretaker to adhere to the following protocols:

  • Isolate the affected animal, particularly from susceptible groups such as young and pregnant horses;
  • Clean and disinfect the trailer after bringing him home;
  • Practice good hand hygiene (e.g., Purell hand sanitizer or hand wipes);
  • Disinfect hand-traffic areas, such as light switches and stall latches, with wipes daily;
  • Wear protective gear, such as gloves and booties, when handling the horse;
  • Place boot baths in the barn aisle, and clean them multiple times a day;
  • Clean that horse’s stall last, using designated muck boots and tools;
  • Don’t spread the horse’s manure. If possible, compost it to kill the pathogens; and
  • Keep common areas, such as feed rooms, and surfaces, such as counters and sinks, clean.

Slovis said he believes educating owners about Salmonella and how to contain it can help prevent panic among owners and outbreaks among horses.

Read his recent study on proper protocols for reducing Salmonella spread on the farm at