Wisconsin mare tests positive for strangles in Jefferson County

Wisconsin has another confirmed strangles case, this time involving a 15-year-old Quarter Horse mare in Jefferson County. The mare tested positive on March 23, 2026, after developing bilateral nasal discharge on March 6, according to an Equine Disease Communication Center alert sourced to the Wisconsin Department of Agriculture, Trade and Consumer Protection. The horse had been exposed to strangles at a previous premises, came from a local rescue, is unvaccinated, and is now under voluntary quarantine. The EDCC listing says four horses were exposed at the current private facility. (equinediseasecc.org)

Why it matters: For equine veterinarians and animal health teams, the case is another reminder that horse movement, especially from rescue or rehoming settings, can carry infectious disease risk even when clinical signs emerge later. Strangles, caused by Streptococcus equi subspecies equi, is highly contagious, can spread through direct contact and contaminated equipment, and may also persist through asymptomatic carriers. AAEP says vaccination is generally risk-based rather than routine for every horse, while Merck notes biosecurity and carrier screening are central to outbreak control. (merckvetmanual.com)

What to watch: Watch for any additional Wisconsin alerts tied to exposed horses on the Jefferson County premises, and for whether quarantine, testing, or tracing identifies a wider exposure chain linked to horse transfers. (equinediseasecc.org)