Update on Kentucky strangles outbreak
Seven confirmed strangles cases among Thoroughbreds at training facilities in Kentucky have initiated an epidemiological investigation. The positive cases have so far only been linked to horses under the care of a single trainer and potentially a second trainer.
At Premises 1 (The Thoroughbred Center), the horses were resampled on April 24 with negative results returned. The horses under the care of the single trainer will be resampled a third time, with the test including examination and flushing of the guttural pouches. The horses under care of a second trainer will also be sampled a third time.
At Premises 2 (Keeneland Race Course), the 15 horses under the care of the two individual trainers were sampled on April 24 and found to be negative. The horses in this barn have now tested negative twice, and investigation has identified no direct exposure to positive horses. The quarantine of Barn 7 at Keeneland has therefore been released, and horses will resume training activity. Their health will still be monitored daily.
At Premises 3 (Triple Diamonds Training Center), the horses residing in the affected barn were sampled, and results are pending.
The seven positive horses moved from the three premises remain under quarantine at a private facility. Prior to releasing these horses, they will be sampled on three separate occasions, which will include endoscopic examination and flushing of the guttural pouches.
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.