California is calling on farriers to practice biosecurity measures after multiple counties are experiencing an uptick in Equine Herpes Myeloencephalopathy (EHM).

The disease is spread by an infected horse’s secretions, including on shared surfaces or equipment. Transferring the disease may be possible via sharing tack or other equipment, including farrier and veterinarian equipment. The disease is spread by aerosolized secretions, direct contact and contact with surfaces containing infected secretions. These surfaces can include clothing and people, and not just equipment. Respiratory shedding of the virus can occur for 7-10 days. 


There is no vaccine available that can prevent EHM.


There has been an increasing number of cases of EHM/Equine Herpes Virus in recent years and in states including California, Michigan, Florida, Ohio and both North and South Dakota. According to a memo from the California Department of Food and Agriculture, the newest cases stem from California, and other reports indicate it is prevalent throughout the state, from Riverside County to San Mateo


If you are or have worked with a horse in a quarantined or otherwise potentially exposed facility, it is recommended that a thorough cleaning of equipment be conducted, as well as following biosecurity guidelines. These measures can help to stop the spread of the disease. Below is California’s protocol for farriers in quarantined barns.

  • California Department of Food & Agriculture (CDFA) Incident Management must be notified.

  • CDFA will designate the approved working area away from other horses in CDFA mandatory quarantined facilities.

  • The infected horse should be the last appointment of the day.

  • The farrier must disinfect all tools between horses and after the last horse. An example of approved disinfectants is 10% bleach (1 part bleach, 10 parts water), Lysol or Noble Outfitters Stall Disinfectant/Biosecurity wash.

  • Must spray mat and shoeing apron with disinfectant, then wash hands and arms, then change to a clean shirt before working on a new horse and after the last horse.

  • Disinfect the cross-ties before, between and after each horse.

  • Wash hands and arms. Dip boots in disinfectant before getting back in your truck.

  • Clean and disinfect tires thoroughly when leaving a quarantined barn.

More information can be found on the CDFA website, Additional information on California’s biosecurity measures can be found here

EHM is caused by EHV, which can cause respiratory disease abortion, neonatal death, and the neurological form of the disease, EHM. The disease is highly contagious and can be deadly for infected animals.