Currently (March 2021) there are numerous reports of EHV across Europe and we are aware that many of our clients may be concerned that their horses may be affected. This information is intended to help owners of sports and pleasure horses.
Equine herpes viruses are a group of viruses that can cause contagious disease in horses. The two most significant types are Equine Herpes Virus 1 (EHV-1) and Equine Herpes Virus 4 (EHV-4) and they are often collectively referred to as Equine Herpes Virus (EHV).
Respiratory EHV is endemic in the UK, which means it is everywhere: clinical signs are often mild and your horse may even have had it in the past without you realising it.
The respiratory form of the disease can be caused by both EHV-1 and EHV4: it is reported that 80-90% of horses are infected with EHV before the age of 2 years old.
The neurological form of the disease is rare and obviously is very serious. Many horses do not survive. This form is usually due to EHV-1.
EHV can also be associated with abortion, still birth and severe neonatal illness.
Some horses are life-long carriers and the virus can be re-activated in these individuals and cause clinical signs and spread to others. Risk factors for re-activation and consequent spread include transport, strenuous exercise, and at equine events.
Most spread of the virus occurs by close horse-to-horse contact, but it can also be spread by sharing equipment such as tack and mucking out tools.
EHV vaccination should not be considered as an alternative to good biosecurity. We encourage horse owners to quarantine all horses newly arrived on their premises.
EHV vaccination should be considered as part of a group preventative health care programme; there is less benefit if an individual horse is vaccinated while the remainder of the horses it lives with are not.
Whilst EHV vaccination reduces shedding of the virus and makes clinical signs milder, it does not necessarily abolish either. However, reducing shedding helps to minimise risk to other horses when a horse is infected with EHV.
There is currently no evidence that vaccination prevents the development of the neurological form of the disease.
Which horses should be vaccinated now?
- Broodmares should receive their EHV vaccinations every year.
- Racehorses fit the general profile of high risk and, depending on the jurisdictions to which they are travelling, vaccination may be obligatory.
What is the profile of horses that are likely to benefit from group vaccination?
- Horses in large livery yards where horses come and go on a regular basis.
- Horses which travel away for competitions, particularly when this involves overnight stays in shared stabling.
- Horses which are living on yards where other horses travel away frequently
If your horse doesn’t fit this profile, vaccination against EHV is not essential at present. Our vets will be happy to discuss your specific circumstances if you require more advice.
Read the updated information from British Equestrian, issued on 18th March 2021.
More information about EHV and EHV vaccinations is available on horsedialog.co.uk
Owners of broodmares and racehorse trainers should refer to Codes of Practice from the HBLB and National Trainers Federaton (NTF). Advice is also available via the EquiBioSafe app (download here for Apple devices, or here for Android)
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