
On May 8, a yearling Gypsy Vanner filly at a private facility in Grey County, Ontario, tested positive for strangles. She sadly passed away after developing multiple draining abscesses, persistent fever, and weight loss.
The filly fell ill after another horse returned from a 90-day training session at a large training facility that had recently experienced a strangles outbreak. Since the return of that horse, five out of six horses on this private farm have contracted strangles. Currently, one senior pony is undergoing supportive treatment.
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 to provide open access to infectious disease information.
About Strangles
Strangles in horses is an infection caused by Streptococcus equi subspecies equi and spreads through direct contact with other equids or contaminated surfaces. Horses that do not display clinical signs can harbor and spread the bacteria, and recovered horses remain contagious for at least six weeks, potentially causing long-term outbreaks.
Infected horses may show a range of clinical signs:
- Fever
- Swollen and/or abscessed lymph nodes
- Nasal discharge
- Coughing or wheezing
- Muscle swelling
- Difficulty swallowing
Veterinarians typically diagnose horses using polymerase chain reaction (PCR) testing with a nasal swab, wash, or an abscess sample, and they treat most cases based on clinical signs, using antibiotics for severe cases. Overuse of antibiotics can hinder the development of immunity in an infected horse. Most horses recover fully within three to four weeks.
A vaccine is available but may not always be effective. Implementing biosecurity measures such as quarantining new horses at a facility and maintaining high standards of hygiene and disinfecting surfaces can help reduce the risk of an outbreak or contain one if it occurs.

