The Arizona Department of Agriculture alerted the Equine Disease Communication Center of one case of neurologic herpesvirus in Maricopa County on March 28.

The 20-year-old Quarter Horse mare had onset of clinical signs on March 25 that included severe neurologic signs. Equine herpesvirus myeloencephalopathy (EHM) was confirmed on March 27. The mare, which was unvaccinated, was euthanized.

This mare was not associated with the previous case reported in Maricopa County on March 26. Seven horses exposed at the mare’s facility are in quarantine.