Two horses in Ontario recently tested positive for strangles. The cases are located in Grey County and the Regional Municipality of Halton. 

In Grey County, a 12-year-old Paint gelding developed clinical signs of strangles on June 23, two weeks after being purchased from someone who buys and sells horses for a living. The horse stopped over at a sales barn in the Regional Municipality of Waterloo for 48 hours before arriving at its new location. He tested positive for strangles on PCR. 

In the Regional Municipality of Halton, a 35-year-old pony gelding tested positive for strangles after developing a single submandibular abscess on June 23. The pony had other significant health issues and was receiving an immune-modulating medication. He was euthanized due to his declining health. The other horses at the facility are being monitored by the attending veterinarian. 

EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.

About Strangles

Strangles in horses is an infection caused by Streptococcus equi subspecies equi and spread through direct contact with other equids or contaminated surfaces. Horses that aren’t showing clinical signs can harbor and spread the bacteria, and recovered horses remain contagious for at least six weeks, with the potential to cause outbreaks long-term.

Infected horses can exhibit a variety of clinical signs:

• Fever
• Swollen and/or abscessed lymph nodes
• Nasal discharge
• Coughing or wheezing
• Muscle swelling
• Difficulty swallowing

Veterinarians diagnose horses using polymerase chain reaction (PCR) testing with either a nasal swab, wash, or an abscess sample, and they treat most cases based on clinical signs, implementing antibiotics for severe cases. Overuse of antibiotics can prevent an infected horse from developing immunity. Most horses make a full recovery in three to four weeks.

A vaccine is available but not always effective. Biosecurity measures of quarantining new horses at a facility and maintaining high standards of hygiene and disinfecting surfaces can help lower the risk of outbreak or contain one when it occurs.