On Sept. 19, a 21-year-old Friesian gelding at a boarding facility in Providence County, Rhode Island, tested positive for strangles. The horse was vaccinated against strangles in April and has had a chronic unilateral nasal discharge since sustaining a head injury as a young horse.Recently, the horse was referred to an ophthalmologist for treatment of a descemetocele. That veterinarian cultured the descemetocele and recoveredStrep. equi equi. Subsequent nasopharyngeal wash yielded a positive PCR for strangles. This sample was determined to be the wild strain, not the vaccine strain.The horse is now quarantined.EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. TheEDCCis an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.About StranglesStranglesin horses is an infection caused byStreptococcus equisubspeciesequiand spread through direct contact with other equids or contaminated surfaces. Horses that arent 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:FeverSwollen and/or abscessed lymph nodesNasal dischargeCoughing or wheezingMuscle swellingDifficulty swallowingVeterinarians diagnose horses using polymerase chain reaction (PCR) 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. Biosecurity measures of quarantining new horses at a facility and maintaining high standards of hygiene and disinfecting surfaces can helplower the risk of outbreakorcontain one when it occurs.