Horses at two barns in Ontario have recently been confirmed positive for strangles. The barns are located in the Regional Municipality of Halton and Middlesex County.
In the Regional Municipality of Halton, a 9-year-old pony mare developed clinical signs on June 17, including fever and submandibular swelling. She was quickly isolated from other horses. Ten additional horses at the boarding facility are exposed and under voluntary quarantine.
In Middlesex County, a 2-year-old Quarter Horse gelding that was recently purchased developed clinical signs on June 13, including fever and submandibular swelling. The horse had been isolated since arrival at the facility and remains under voluntary quarantine. Three additional horses at the facility are potentially exposed.
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.
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:
- 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.