Streptococcus equi subsp. Equi is the pathogen that causes the well-known disease; strangles. Strangles is highly contagious between horses- bacteria are transmitted through direct contact with an infected horse, or through contact with contaminated objects such as brushes, water buckets, and halters.

Researchers recently confirmed that proper sanitation of most items found in the barn can effectively eliminate viable S. equi contamination. In the study they examined the cleaning and sanitation of materials commonly found in the barn, such as wood, concrete, and plastic, along with leather, and polyester webbing halters, which they inoculated with a 24-hour laboratory culture of S. equi.

Different ways to kill strangles-causing bacteria

In field conditions, S. equi can survive on surfaces such as wood and glass for up to 72 days, unless in summer conditions, where exposure to direct sunlight and high temperatures can reduce its survival to just one to three days.

When cleaning the stable of an infected horse, first remove visible organic material then use a disinfectant. Researchers on the study cleaned half of the contaminated items, leaving those remaining as a control group. They scrubbed each item in the sanitation group with warm water and 15% alcohol ethoxylate detergent for 1 minute, then waited 10 minutes before rinsing with tap water. After two hours, they soaked the items in a potassium monopersulfate, maleic acid, and sulfamic acid disinfectant, then left them to dry for two days.

The research team waited three days before washing a group of the polyester halter webbing pieces in a commercial washing machine at 40 degrees Celsius (104 degrees Fahrenheit) for 39 minutes, using an alkaline cleaner, before air-drying half and tumble-drying the other half at 70 degrees Celsius (158 degrees F) for 60 minutes. They washed the other group of halter pieces in the machine at 60 degrees Celsius (140 degrees F) for 43 minutes.

They performed bacterial sampling by wiping sterile cloths on each material’s surface for one minute, then processed these cloths for laboratory culture.

Don’t toss that strangles horse’s leather halter

Ultimately, the scientists proved these methods were effective in cleaning equipment contaminated with S. equi. “Materials such as polyester webbing halters require machine washing at 60 degrees Celsius to eliminate viable S. equi,” said Anneli Ryden, PhD, corresponding author on the study.

Of all materials tested, the nonporous ones were most easily disinfected. “Leather appears to poorly support the long-term survival of S. equi,” said Ryden.

With routine cleaning and sanitation of most equipment and surfaces in equine stables, owners can effectively eliminate contamination by viable S. equi, said Ryden.