Three horses in Sweet Grass County, Montana, have tested positive for strangles, according to the state veterinarian. A total of 70 horses have been exposed to the disease, and the affected horses are currently under quarantine.
EDCC Health Watch is a program by Equine Network that utilizes information from the Equine Disease Communication Center (EDCC) to create and distribute verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations, providing open access to infectious disease information.
About Strangles
Strangles is an infection in horses caused by Streptococcus equi subspecies equi, transmitted through direct contact with other equids or contaminated surfaces. Even horses not showing symptoms can carry and spread the bacteria, with recovered horses remaining contagious for up to six weeks, potentially leading to long-term outbreaks.
Common clinical signs of infected horses include:
- Fever
- Swollen or abscessed lymph nodes
- Nasal discharge
- Coughing or wheezing
- Muscle swelling
- Difficulty swallowing
Veterinarians typically diagnose strangles using polymerase chain reaction (PCR) testing with nasal swabs, washes, or abscess samples. Treatment is based on clinical signs, with antibiotics used for severe cases. Overuse of antibiotics can hinder the development of immunity in infected horses, but most cases recover fully within three to four weeks.
While a vaccine is available, it may not always be effective. Implementing biosecurity measures such as quarantining new horses and maintaining strict hygiene practices can help reduce the risk of outbreak or contain one if it occurs. Learn more about protecting your horse and managing strangles on the farm.