Update on EHM - Northumberland County and Durham County, Ontario
April 16, 2021 The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has been notified that a horse was removed from a facility in Northumberland County where cases of equine herpes myeloencephalopathy (EHM) caused by equine herpesvirus-1 (EHV-1) infection have been diagnosed. The movement of this horse was contrary to veterinary advice and the voluntary animal movement restrictions implemented by the facility owner. 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. On April 10, 2021 OMAFRA was notified of a case of EHM in Durham County. This horse had left an infected Northumberland County facility on April 1, 2021; the same day the index horse from that facility was referred to an equine hospital for suspected treatment of EHM. The mare is at a private farm and is under veterinary supervision. <read advisory here>
New cases of EHM
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.
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.
EHV-1 does not pose a threat to public health or food safety.
EHV-1 infection is immediately notifiable by laboratories to OMAFRA under the Animal Health Act. Attending veterinarians concerned about potential cases of EHV-1 infection may contact an OMAFRA veterinarian through the Agricultural Information Contact Centre at 1-877-424-1300.
EHV-1 infection in horses can cause
respiratory disease, abortion, neonatal foal death,
and/or neurological disease.
Because a fever (greater than 101.5 °F or 38.6 °C) may be the first indication of infection, the temperature of potentially exposed animals should be monitored and recorded twice daily for 21 days and any abnormalities discussed with a veterinarian. Neurological signs, if they develop, may include loss of balance, hind-limb weakness, difficulty urinating, decreased tail tone, depression and being down and unable to rise. It is important that a veterinarian assess horses demonstrating neurological signs since it can be difficult to distinguish this from other serious diseases such as rabies.
EHV-1 infection is easily spread to other horses by nose-to-nose or close contact with an infected horse, by sharing contaminated equipment including bits, buckets and towels or by the clothing and hands of people who have recently had contact with an infected horse. It is important, therefore, to restrict movement for 21 days of both people and horses where EHV-1 has been diagnosed. Any person leaving a facility to care for or be in contact with horses elsewhere should change their clothes, shoes/boots and wash their hands before leaving the property. Facility owners should also inform all service providers that have attended the facility within the previous week, including, but not restricted to, veterinarians, farriers, feed suppliers and transporters, of the presence of the virus at the facility so they can take appropriate precautions.
Prevention is the best medicine
Biosecurity is key to preventing spread of EHV-1. Implementing routine biosecurity measures is the best way to minimize viral spread and should be in place at all times to prevent a disease outbreak. Such measures include hand hygiene and basic cleaning and disinfection practices. Horses that have been shipped long distances should be segregated for 14 days prior to entering the general population.
EHV-1 vaccines marketed for prevention of respiratory disease may reduce viral shedding but are not protective against developing the neurological form of the disease in the vaccinated animal.
For additional information:
ALBERTA VETERINARY MEDICAL ASSOCIATION AND ALBERTA EQUESTRIAN FEDERATION