BEWARE ARENA AIR
Bacteria-laden dust in riding rings poses a health risk to horses and riders alike.
A study from Germany underscores the potential dangers that bacteria-laden arena dust pose to horses and riders alike.
Although recurrent airway obstruction and inflammatory airway diseases in horses are caused by many factors, “exposure to inhaled dust and attached bacteria and fungi is a major contributor to respiratory problems,” says Nina Volkmann of the Institute for Animal Hygiene, Animal Welfare and Farm Animal Behavior of the University of Veterinary Medicine Hannover.
To determine the levels of bacteria in arena dust, the researchers collected air samples from four indoor riding arenas monthly over a oneyear period.
On each occasion, a preliminary sample was taken before a riding session began— when the footing had been undisturbed for 10 hours— and a second one was taken immediately after riding concluded. Researchers collected samples at four points along both the short and long sides of the arena and at two different heights, one approximately at the level of a horse’s nostrils and another at the height of the rider’s head.
Analysis of the 1,335 collected samples revealed that the bacterial loads in the airborne particles in all four arenas increased significantly after the footing had been stirred up by riding. Researchers found that 80 percent of the airborne bacteria was Staphylococcus xylosus.
“The exact impact of the predominant species identified in this study ( Staphylococcus spp.) on the health of riders and horses remains unknown, but Staphylococci have been described to be involved in respiratory diseases,” says Volkmann. “Moreover, these bacteria do not originate from the environment but from warm-blooded species, which means they are important indicators of contamination. If such indicators occur, it can be assumed that other bacteria such as Enterococci or Streptococci are also present in the air of riding arenas, which can have further effects on the development of diseases.”
Even if a horse doesn’t have any respiratory conditions, the inhalation of dust and the bacteria it carries can be harmful, says Volkmann. “Previous studies verified that higher dust environments are associated with an increased degree of airway inflammation and might facilitate the development of that condition in otherwise healthy horses,” she says. “Contaminated breathing air (in riding arenas) should, therefore, always be avoided—in healthy horses as well as in horses with known respiratory illness.”
The researchers were surprised to find no significant difference between the bacterial loads at the horse’s nostril level and the rider’s level, says Volkmann. “We would have expected to find higher bacterial burden at the height of the horses’ breathing zone, as the footing material was probably a considerable source of airborne bacteria and, thus, the horses’ noses were closer to this source. However, the air circulation in the arenas is an important factor, linking the arena to other adjacent places where dust is present, such as the barn area with straw and hay.”
That means that not only are riders at risk, but people on the ground in the arena are, too. “Depending on the condition of the arena, even instructors can experience health impairment. Breathing is deeper and the potential exposure to air pollution is worse when performing or riding, but often instructors stay longer in arenas than single riders.”
There are ways to reduce the amount of dust and bacteria in riding areas, says Volkmann. “Picking up manure from arenas will reduce the risk of inhaling harmful microorganisms—for both horses and riders, given that strains of Escherichia coli and other fecal bacteria can dwell in the litter or footing material and can settle on the dust particles,” she says. “Moreover, the footing material should be regularly maintained, pulled straight and watered to avoid dust development.”
Reference: “Bacterial burden in the air of indoor riding arenas,” Agriculture, December 2022