
A draft cross filly in the United Counties of Stormont, Dundas, and Glengarry, Ontario, has been diagnosed with strangles. The filly showed symptoms on Jan. 19, including fever, nasal discharge, and a swollen lymph node.
The filly and her dam were purchased from a sale a week before the filly started showing symptoms. The mare also had mild nasal discharge and is suspected to have strangles as well.
EDCC Health Watch is a program by Equine Network that uses information from the Equine Disease Communication Center (EDCC) to provide verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations to offer accessible infectious disease information.
Understanding Strangles
Strangles in horses is caused by the bacteria Streptococcus equi subspecies equi and spreads through direct contact or contaminated surfaces. Infected horses can spread the bacteria even without showing symptoms, and recovered horses can remain contagious for up to six weeks, potentially leading to outbreaks in the long term.
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 prescribed for severe cases. Overusing antibiotics can hinder the horse’s 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.

