EHV-1 neurological Equine Herpes Virus – what’s the latest update?
Just as competitors and horse owners in the world’s equestrian communities are preparing to get out and about again as the latest COVID restrictions ease, there’s another catastrophe about to hit the unprepared or, the downright unlucky. There’s no doubt most people will have heard about the tragic cases of EHV-1 that hit Spanish show jumping venues with devastating consequences and, the subsequent fatalities – currently official confirmed figures number 12, although different numbers are apparently circulating on social media.
Alarmingly, despite acting quickly and taking every precaution, the movement of horses returning to their home countries has resulted in confirmed, related cases in the Middle East, Belgium, Spain, France, Germany, Italy, Sweden and Switzerland. (There is currently an outbreak in the USA but this is unrelated).
In the UK the British Equine Veterinary Association (BEVA) are urging horse owners and competitors returning to the UK to take very strict biosecurity measures. This includes horses not at the event but also, those passing through any of the European countries that currently have cancelled international events.
David Rendle, Chair of BEVA’s Health and Medicines Committee said: “The consequences of this outbreak have been devastating and understandably, there is anxiety that horses returning to the UK may be carrying the virus and infection may spread back in the UK. To prevent this from happening, it is essential that returning competitors comply with the quarantine plans that have been put in place by British Showjumping.
“If returning horses are quarantined effectively, and ideally screened using suitable laboratory tests on their return, then the risk to the wider UK equine population is very small,” said David. “British Showjumping and the BEF have acted swiftly and responsibly with support from BEVA to put controls in place. Assuming that everyone continues to act responsibly and follow the advice then the risk of this fatal disease spreading among UK horses will be minimised.”
This strain of EHV-1 is particularly aggressive; it is a highly contagious virus that spreads between horses that are in close contact with one another. It can spread on people or objects but, is more likely to spread horse to horse within the stable environment, and particularly in enclosed buildings such as American barns with shared air spaces. It does not spread over long distances in the air and, is unlikely to spread between different buildings or yards without movement of horses, people or objects.
For more information about EHV-1 and what to do if you suspect a case, follow the link to the FEI information sheet: FACT SHEET.
What do British showjumping say about EHV vaccination?
Vaccination decreases nasal shedding of virus if a vaccinated horse does become infected. Therefore, vaccination decreases the total amount of virus in the environment which in turn reduces the likelihood that other horses become infected. However, no EHV-1 vaccine is registered for use to prevent neurological disease and, vaccination has not been shown to reduce the risk of neurological signs.
Travelling, housing in large groups, and mixing of horses are all recognized risk factors for precipitating clinical signs of neurological EHV. Therefore, our strong advice is that travel to competitions in Europe should be avoided while the current outbreak remains active regardless of whether horses are vaccinated or not.
It is essential that vaccination is not considered a means to overcome sub-optimal biosecurity. Avoiding mixing in at risk populations, close monitoring, early diagnosis and isolation of suspect horses remain the cornerstones of prevention regardless of vaccination status.
Vaccination of animals known or suspected to have recently been in contact with EHV-1 is not recommended. Although vaccination will reduce the risk for the horse population as a whole, there is some evidence from previous outbreaks that recent vaccination is a risk factor for development of neurological signs in individuals, thus advice for this group of horses is less definitive.
As it is currently unclear how long the current outbreak will remain active in Europe, we are not currently recommending vaccination for horses which are scheduled to travel to Europe in the next few weeks. British Showjumping will continue to advise its members as the European outbreak progresses.
EHV is an endemic disease in Europe, therefore it will continue to represent an ongoing threat after the current outbreak is over. Therefore, we advise EHV vaccination for horses travelling to Europe this summer and beyond. For horses to remain protected it is important that once the primary course has been given, vaccination should be continued in future with boosters required every six months.
This advice has been prepared by members of the BEF Equine Infectious Disease Advisory Group with support from British Equine Veterinary Association.