The Wisconsin Department of Agriculture, Trade and Consumer Protection has reported four new strangles cases in the state.
A 13-year-old mare in Brown County presented with lymphadenopathy (swelling or abscessation of the lymph nodes under the jaw) and fever. Three horses were exposed at the boarding facility, which is now under voluntary quarantine.
A horse in Racine County presented with nasal discharge. The 15-year-old Belgian gelding was reportedly purchased at an auction in Illinois in late May, and the facility where he currently resides is under voluntary quarantine.
Two horses in Sheboygan County tested positive at a boarding facility where three horses were suspected positive and 27 were exposed. A Miniature Horse gelding presented with unilateral nasal discharge on June 8 and confirmed positive on June 11. A 15-year-old Warmblood mare presented on June 9 with lymphadenopathy, nasal discharge, and fever and was also confirmed positive on June 11. A yearling Warmblood filly on the property also presented with a fever, and a 22-year-old Paint mare had an abscess and draining lymph node, but tests have not confirmed their diagnosis. The facility is under voluntary quarantine.
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. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.
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:
- Swollen and/or abscessed lymph nodes
- Nasal discharge
- Coughing or wheezing
- Muscle swelling
- Difficulty swallowing
Veterinarians 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 help lower the risk of outbreak or contain one when it occurs.