Confirmed Case of Strangles in Michigan Results in Euthanasia of Young Colt

On April 1, health officials confirmed a case of strangles in Macomb County, Michigan, involving a suckling Quarter Horse colt. The young horse began showing clinical signs on March 15, including fever, lethargy, enlarged lymph nodes, weakness in the hindlimbs, and eventually recumbency. Due to the severity of his condition, the colt was humanely euthanized.

The case was reported by the Equine Disease Communication Center (EDCC) through its EDCC Health Watch, a trusted source for real-time updates on confirmed equine disease outbreaks across the country.

Strangles is a highly contagious bacterial infection caused by Streptococcus equi subspecies equi. It spreads easily through direct contact with infected horses or via contaminated objects and environments. Importantly, horses may carry and shed the bacteria without showing clinical symptoms, and recovered horses can remain contagious for at least six weeks.

Symptoms & Diagnosis:

• Swelling and abscessation of lymph nodes
• Nasal discharge
• Fever and depression
• In some cases, difficulty breathing or swallowing
• Diagnosis is typically confirmed via PCR testing using samples from nasal swabs, washes, or abscesses.

Treatment & Prevention:

While many cases resolve within 3–4 weeks, treatment is usually supportive. Antibiotics are used selectively, as overuse may interfere with natural immune response. A vaccine is available, but its efficacy can vary depending on the horse and situation.

Preventive biosecurity practices remain the best defense:

• Isolate new arrivals for 2–3 weeks
• Disinfect equipment and stalls regularly
• Avoid sharing tack, buckets, and grooming tools
• Monitor herd health and respond promptly to symptoms