Michigan strangles case highlights ongoing equine biosecurity gaps

Version 1 — Brief

A 2-year-old Quarter Horse gelding in Marquette County, Michigan, tested positive for strangles on March 5 after developing bilateral nasal discharge on February 23, according to an EDCC Health Watch report published March 26. The horse is recovering, one additional horse is suspected positive, and two others were exposed. A separate EDCC/Equus report from Wisconsin adds a newer, clearer case than the one previously indexed online: on March 23, a 15-year-old Quarter Horse mare in Jefferson County tested positive after developing nasal discharge on March 6. The mare had come from a local rescue, had been exposed at her previous premises, and is currently quarantined. (equusmagazine.com)

Why it matters: For equine veterinarians and barn managers, the Michigan and Wisconsin cases are reminders that strangles remains a routine but disruptive biosecurity problem, especially where horses are newly introduced, moved between facilities, or arrive from rescue settings. Strangles is caused by Streptococcus equi subspecies equi and spreads through direct contact and contaminated surfaces; horses without obvious signs can still spread it, and recovered horses may remain contagious for at least six weeks. Typical signs include fever, swollen or abscessed lymph nodes, nasal discharge, coughing or wheezing, muscle swelling, and difficulty swallowing. Michigan lists strangles as a reportable equine disease, while Wisconsin requires reporting of animal diseases under state rules and notes that suspected cases may trigger investigation and quarantine while testing is pending. EDCC-linked biosecurity guidance emphasizes separating new or returning horses for at least 14 days, monitoring temperatures twice daily, and avoiding shared equipment or horse-to-horse contact during transport. (michigan.gov)

What to watch: Watch for any updated EDCC or state animal health posting on whether additional exposed horses in Michigan convert to confirmed positives and whether the Jefferson County, Wisconsin, quarantine leads to more linked cases. PCR testing using a nasal swab, wash, or abscess sample remains the standard diagnostic route, and most horses recover in three to four weeks, though severe cases may need antibiotics. (equusmagazine.com)