
On Jan. 15, a Miniature Horse in Dorchester County, Maryland, was diagnosed with strangles after showing clinical signs on Jan. 12. The horse is currently under quarantine.
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, offering open access to infectious disease information.
About Strangles
Strangles is an equine infection caused by Streptococcus equi subspecies equi, transmitted through direct contact with infected horses or contaminated surfaces. Even asymptomatic horses can carry and spread the bacteria, 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 typically diagnose strangles using polymerase chain reaction (PCR) testing with samples from nasal swabs, washes, or abscesses. Treatment is usually based on clinical signs, with antibiotics prescribed for severe cases. Excessive antibiotic use can hinder the horse’s ability to develop immunity. Most horses recover fully within three to four weeks.
While a vaccine is available, its efficacy can vary. Implementing biosecurity measures such as quarantining new arrivals and maintaining strict hygiene practices can help reduce the risk of outbreaks and contain them if they occur. Learn more about protecting your horse from strangles and managing outbreaks on the farm.

