One horse in Grays Harbor County recently tested positive for strangles. The horse lives at a private facility, and it is unknown if additional horses are exposed.

Strangles in horses is an infection caused by Streptococcus equi subspecies equi and spread through direct contact with other equids or contaminated surfaces. Horses that aren’t showing clinical signs can harbor and spread the bacteria, and recovered horses remain contagious for at least six weeks, with the potential to cause outbreaks long-term.

Infected horses can exhibit a variety of clinical signs:

Fever

Swollen and/or abscessed lymph nodes

Nasal discharge

Coughing or wheezing

Muscle swelling

Difficulty swallowing

Veterinarians diagnose horses using polymerase chain reaction testing with either a nasal swab, wash or an abscess sample, and they treat most cases based on clinical signs, implementing antibiotics for severe cases. Overuse of antibiotics can prevent an infected horse from developing immunity. Most horses make a full recovery in three to four weeks.

A vaccine is available but not always effective.