Commenting on the on-going outbreak of Equine Herpesvirus-1 in horses in continental Europe, the Minister for Agriculture Food and the Marine, Charlie McConalogue T.D., has urged all players in the equine industry to respond to the increased risk that this poses to the equine population in Ireland and to double down on their biosecurity practices and measures.
The Minister stated, “I am aware that Irish horses have been competing across Europe in recent weeks. My officials met with representatives of Horse Sport Ireland and the Irish Equine Centre yesterday (2 March) to develop an appropriate risk mitigating response. Whilst this is not a notifiable disease, given the extent that the virus seems to have spread across Europe and the description of the clinical outcome, I strongly endorse the recommendation from that meeting that all those competing horses, on returning to Ireland follow the EHV-1 protocol for returning FEI horses, to isolate and carry out two PCR tests prior to completing quarantine.”
EHV is a herpes virus that is spread widely across the world including Ireland, where it usually manifests as a respiratory of reproductive disease and occasionally in a paralytic form. Given its ubiquitous nature and the availability of a vaccine, EHV is not a notifiable disease. The disease can be contained by isolation and testing. The Irish Equine Centre is an OIE reference laboratory for EHV and provides support to industry with their expert advice.
EHV is covered by industry codes of practice, in particular the prevention of EHV infection in breeding stock through good management and hygiene practices as well as regular vaccination. EHV has no zoonotic impacts.
The Minister concluded by recalling the critical importance of animal health in all animal based production systems and no more so than in equine sectors.
Note for Editors:
- Clinical Signs:
EHV-1 may manifest in many ways. Typically horses will develop a fever, and develop respiratory signs such as a serous (thin, watery) nasal discharge and occasional cough. Some horses may also show submandibular lymphadenopathy (enlarged lymph nodes under their jaw) and ocular discharge.
In some cases, when the virus has a specific genotype, EHV-1 can manifest with neurological symptoms. These can be of variable severity, ranging from mild ataxia (in co-ordination) and paresis (weakness), to full recumbency with an inability to stand as well as urinary and fecal incontinence.
EHV-1 infected pregnant mares will likely suffer a late-term abortion of their pregnancy. In some circumstances, if they only became infected with the virus late in their gestation, they may not abort, but give birth to a foal that is infected with the virus, which will likely die of severe complications in their respiratory and hepatic systems as well as bone marrow dysfunction. Ensuring broodmares are properly vaccinated for EHV-1/EHV-4 is important as part of good biosecurity and prevention of EHV infection in breeding stock.
- Summary of Outbreak on the Continent:
An outbreak of Equine Herpes Virus (EHV-1) occurred at the CES Valencia Spring Tour (ESP), with horses that were in attendance at the venue from at least 1st February 2021 potentially exposed to the virus. Numerous horses at the venue subsequently displayed clinical symptoms of the virus, including neurological symptoms, and to-date four horses have died. A certain number of horses which left Valencia and travelled back to their home countries (FR, BEL, DE) have subsequently developed clinical signs of the virus as well. Veterinary authorities are on-site in Valencia to deal with the outbreak, carry out the necessary testing and treatment of clinically-affected animals. Those horses requiring more intensive care are being managed in isolation units in tertiary level equine hospitals.