On April 11, Dr. Richard Wilkes, state veterinarian for the Virginia Department of Agriculture and Consumer Services, announced that a horse in Northern Virginia tested positive for the equine herpesvirus myeloncephalopathy, a neurological disease caused by the equine herpes virus-1. The horses on that farm in The Plains in Fauquier County will remain under quarantine for 21 to 28 days from the last exposure to the virus, the incubation period for EHM.
Diagnostic samples were submitted to the VDACS Regional Animal Health Laboratory System after the horse had a fever for three days and showed neurological signs compatible with EHM. The affected horse was euthanized on April 11. VDACS field veterinarians have launched an epidemiological investigation to assess the risk to other horses and farms.
An update on the VDACS website April 12 stated: Initial epidemiological investigation results indicate that four horses exposed to the infected horse left the farm in the last 28 days. All four of these horses were shipped out-of-state, and the state veterinarians in those two states receiving these horses have been notified. There are no new cases on the affected farm, and VDACS has not identified any contact of exposed horses with any other horses off the affected farm in Virginia. As of April 13, VDACS confirmed none of the exposed horses were exhibiting fevers or neurological symptoms.
On April 14, Wilkes commended farm management and their veterinarian at the Fauquier farm for their quick recognition of the clinical signs and for initiating the testing that led to the diagnosis of EHM. Although he still urged horse owners to prevent contact of healthy horses with any that may be exposed to EHM infected horses, he said the rapid detection of disease in the initially infected horse may have helped limit the scope of this disease event.
“The farm management kept excellent records of movement on and off the farm that provided excellent information for VDACS staff to identify exposures of other horses,” he said.
VDACS issued a reminder to horse owners that strict biosecurity can minimize the risk of spreading the virus by minimizing contact with other horses, keeping all shared equipment disinfected, and isolating and monitoring horses that have traveled recently. Horse caretakers can monitor their horses by taking their temperatures and reporting elevated temperatures to their veterinarians.