On April 18, a Thoroughbred filly in Fayette County, Kentucky, was confirmed positive for strangles, and 18 horses at the training facility were exposed. Further epidemiologic investigation has allowed for updated information on the current status of racing in Kentucky.
At The Thoroughbred Center, all 19 horses in an affected barn were tested, and one horse was confirmed positive. That horse was stalled next to the index case. Both horses have been removed from the facility and remain isolated at a separate facility. The remaining horses in the barn will remain isolated and are being monitored daily for signs of illness. They will be resampled next week.
The same trainer responsible for the positive horses at The Thoroughbred Center has 19 horses stabled at a barn at Keeneland Race Course. These horses were sampled and moved offsite to a private isolation where they remain under quarantine with daily monitoring. PCR testing on these horses revealed one asymptomatic horse as having a low level of S. equi DNA. The horses will be resampled next week.
The same trainer has eight horses stabled in a single barn at a private training facility in Fayette County. An additional trainer has 19 horses stabled in this barn. All horses have been examined and tested for strangles. The results are pending.
So far, the investigation has found no evidence of the disease-causing organism beyond horses under the care of the single trainer. The Kentucky Department of Agriculture remains confident in receiving horses from The Thoroughbred Center (TTC) to race at Keeneland. Horses originating from TTC are being examined the morning of shipping.
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.