On Aug. 5, state officials confirmed two new strangles cases in Osceola County, Florida, and Ionia County, Michigan.
The Florida Department of Agriculture and Consumer Services confirmed a 17-year-old Miniature Horse mare in Osceola County positive for strangles. She presented on July 25 with mucopurulent (containing mucus and pus) nasal discharge. The horse rescue where she resides is under official quarantine. This marks the 40th confirmed case of strangles in Florida in 2022.
Additionally, the Michigan Department of Agriculture and Rural Development confirmed a vaccinated 19-year-old Quarter Horse gelding in Ionia County positive for strangles. He presented with fever and nasal discharge on July 31. He is recovering, and the facility where he resides is under voluntary quarantine. A new horse was added to the property within the last 30 days; three horses on the property are currently ill, with two others exposed.
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.