A 2-year-old Standardbred filly in the District of Cochrane, Ontario, has been diagnosed with strangles. The filly showed symptoms on Feb. 11, including a swollen head and enlarged lymph nodes. A yearling filly in the same pen also developed purulent nasal discharge.
EDCC Health Watch is a program by Equine Network that uses information from the Equine Disease Communication Center (EDCC) to create and share verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations to provide accessible infectious disease information.
About Strangles
Strangles in horses is caused by Streptococcus equi subspecies equi and spreads through direct contact or contaminated surfaces. Infected horses can transmit the bacteria even without showing symptoms, and recovered horses can remain contagious for up to six weeks, potentially leading to long-term outbreaks.
Common clinical signs of strangles include:
- Fever
- Swollen or abscessed lymph nodes
- Nasal discharge
- Coughing or wheezing
- Muscle swelling
- Difficulty swallowing
Veterinarians diagnose strangles using PCR testing with samples from nasal swabs, washes, or abscesses. Treatment is usually based on clinical signs, with antibiotics reserved for severe cases to prevent overuse and hinder immunity development. Most horses recover fully within three to four weeks.
Although a vaccine is available, its effectiveness varies. Implementing biosecurity measures such as quarantining new horses and maintaining high hygiene standards can help reduce the risk of outbreaks or contain them when they occur. Learn more about protecting your horse from strangles and how to manage outbreaks on the farm.