Equine strangles is a highly contagious and common respiratory disease in horses, donkeys, and mules, caused by the bacterium
Streptococcus equi subspecies
equi. It primarily affects the upper respiratory tract, leading to painful abscesses in the lymph nodes beneath the jaw and in the throat area. The organism spreads rapidly through direct contact, airborne droplets, and contaminated objects and can remain viable in the environment for weeks, representing a significant infectious threat in equine populations.
Clinical signs can develop 3 to 14 days after exposure, usually starting with fever, followed by nasal discharge, depression, and swollen lymph nodes beneath the jaw and in the throat area. These enlarged nodes may compress the airways, causing noisy breathing or difficulty swallowing. Additional clinical signs may include decreased appetite and soft, non-productive cough. Complications can include infection draining into the guttural pouches, spread of abscesses to other body regions (called “bastard strangles"), or other immune-mediated issues. Disease severity and duration vary by age and immune status, with young or naive horses typically having worse clinical signs.
Outbreak Information and Updates
For information on where strangles outbreaks have been reported or are currently occurring in the United States, visit the
Equine Disease Communication Center Strangles page.
Streptococcus equi equi Cases in Oregon
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