On April 12, the Idaho Department of Agriculture confirmed a case of equine herpesvirus myeloencephalopathy in Caribou County. There is an official quarantine.
The 24-year-old pony mare had onset of clinical signs on April 5. Those signs included loss of appetite, depression, mild nasal discharge, nystagmus, mild ocular discharge and recumbency. The unvaccinated mare was euthanized.
There have been at least 16 reported cases of EHM this year in the United States. This is the second case reported in Idaho in 2019.