We reported on Sunday that one horse that had attended the Woodside Spring Classic had an elevated temperature. After receiving a negative test on Tuesday, the horse was tested for the second time. Today, the test came back positive for EHV-4 and Streptococcus equine.
At this point, there have been no other reports of horses with temperatures or any other symptoms. We will keep you informed as we receive any additional information.
We urge you to remain vigilant and stay closely connected to the CDFA Website for the most up-to-date information and updates. 
Basic biosecurity measures to follow to decrease potential disease spread at equine events include:
  • Limit horse-to-horse contact
  • Limit horse-to-human-to-horse contact
  • Avoid use of communal water sources
  • Avoid grazing horses at events and in communal areas
  • Avoid sharing of equipment unless thoroughly cleaned and disinfected between uses
  • Monitor your horse for clinical signs of disease and report any temperature over 102°F to your veterinarian

A Message from Dr. Runk

The following information is being provided to update owners and trainers regarding the febrile horse transported from The Horse Park at Woodside to the Veterinary Medical Teaching Hospital at UC Davis on Sunday, May 9. The horse was PCR negative for EHV-1 and several other common equine respiratory viruses as well as Streptococcus equine on his initial diagnostic testing. To date, this horse has not developed any neurologic signs but has remaining febrile at the VMTH. Repeat diagnostic testing has revealed that the horse is now positive for EHV-4 and Streptococcus equi. There are nine known equine herpes viruses, with EHV-4 primarily causing respiratory disease and occasional abortion in pregnant mares. EHV-1 and EHV-4 prevention is commonly achieved by routine vaccination to prevent Equine Rhinopneumonitis (Rhino) and is usually paired with Influenza (Flu). Horses can become latently infected by EHV-4 and shed this virus in low numbers during times of stress or illness. Strep. Equi aka “Strangles” is a bacterial infection that is spread by nasal secretions and causes fevers and swollen lymph nodes. Since the horse from Woodside was negative on initial PCR testing for EHV-4 and Streptococcus equine, it was likely not shedding significant levels of virus or bacteria while at the show. It is recommended that trainers and owners continue to follow suggested guidelines on return to their home facilities. This should include twice-daily temperature monitoring and isolation if possible. Should your horse show signs of a fever and/or nasal discharge, we ask that you contact your veterinarian for further evaluation, testing and diagnosis.
Please feel free to reach out with any questions or concerns, and in the meantime, please closely follow the recommended protocols to reduce the risk of transmission of communicable diseases.