Neurologic Equine Herpesvirus Confirmed in Ontario, Canada

An aged mare in Nothumberland County, Ontario, was confirmed with neurologic equine herpesvirus.

An aged mare in Nothumberland County, Ontario, was confirmed with neurologic equine herpesvirus. iStock/Ranier Lesniewski

Update 4/16/2021 

Original alert: On April 10, 2021, OMAFRA was notified of a case of EHM in Durham County. This horse had left the same Northumberland County facility on April 1, 2021; the same day the index horse was referred to an equine hospital for suspected treatment of EHM. The mare is at a private farm and is under veterinary supervision. Biosecurity protocols and voluntary animal movement restrictions have been implemented. 

On April 13, 2021, OMAFRA was notified of a confirmed case of EHM at the Northumberland county facility. The mare showed signs of ataxia and is isolated at the facility where she is receiving veterinary treatment.

Original Article

The Ontario Ministry of Agriculture and Food (OMAFRA) stated that a 24-year-old draft cross mare in Northumberland County, Ontario, Canada, was confirmed with neurologic equine herpesvirus (also called equine herpesvirus myeloencephalopathy or EHM). She had onset of clinical signs on March 31 that included ataxia and difficulty urinating. She was confirmed positive on April 6. 

The affected horse is being treated at a referral hospital and is recovering. No other horses on the property are showing clinical signs. Under veterinary supervision, the facility manager has instituted biosecurity protocols and animal movement restrictions. 

For more information about neurologic equine herpesvirus read this Fact Sheet.

Information for this report was provided by the Equine Disease Communication Center.

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