
Two cases of strangles have been reported in Wisconsin involving horses.
In Sheboygan County, a 2-year-old Quarter Horse filly tested positive for strangles on April 10 after showing symptoms such as cough, nasal discharge, and swollen lymph nodes with abscesses. Two more horses are suspected to have the disease, and 13 horses have been exposed.
In Green County, a yearling Miniature Horse filly also tested positive for strangles on April 17. It is currently unknown if other horses have been exposed in this case.
EDCC Health Watch is a marketing program by Equine Network that uses information from the Equine Disease Communication Center (EDCC) to provide verified equine disease reports. The EDCC is a nonprofit organization supported by industry donations to offer accessible infectious disease information.
Understanding Strangles
Strangles in horses is caused by Streptococcus equi subspecies equi and spreads through direct contact or contaminated surfaces. Infected horses can carry and spread the bacteria even without showing symptoms, and recovered horses can remain contagious for up to six weeks, potentially leading to long-term outbreaks.
Common clinical signs of strangles in horses include:
- Fever
- Swollen or abscessed lymph nodes
- Nasal discharge
- Coughing or wheezing
- Muscle swelling
- Difficulty swallowing
Veterinarians typically diagnose strangles using polymerase chain reaction (PCR) testing with samples from nasal swabs, washes, or abscesses. Treatment is usually based on clinical signs, with antibiotics prescribed for severe cases. Overusing antibiotics can hinder the horse’s ability to develop immunity. Most horses recover fully within three to four weeks.
Although a vaccine is available, it may not always be effective. Implementing biosecurity measures such as quarantining new horses and maintaining high hygiene standards can help reduce the risk of an outbreak or contain it if one occurs.

