Health and Welfare

EHV:

THE RISK HASN’T GONE AWAY

JUST BECAUSE EHV IS NO LONGER MAKING EQUESTRIAN NEWS HEADLINES, THE RISK HASN’T GONE AWAY. THE OUTBREAK IN VALENCIA EARLIER THIS YEAR MAY NOW BE SLIPPING TO THE BACK OF EVERYONE'S MINDS, BUT NOW IS EXACTLY THE TIME EVERY HORSE OWNER SHOULD BE MAKING SURE THEIR BIOSECURITY PROTOCOLS ARE UP TO DATE AND DISCUSSING VACCINATION WITH THEIR VET, SAYS ZOETIS VET WENDY TALBOT.

Living in a world with Covid-19 has given us a reality check about how airborne disease can take hold and wreak havoc in a matter of months.

If there could be a small upside for horse owners from the pandemic it may be that it has helped to clarify the importance of vaccination and biosecurity to protect human health. These should remain our watchwords to minimise infectious disease risks for our horses too.

Understanding EHV Equine Herpes Virus (EHV) is a contagious viral infection causing respiratory disease, abortions and neurological disease. Like the human cold sore virus, EHV lies dormant in the majority of horses after they recover from infection and it will periodically recur, especially in times of stress such as travelling or mixing with other horses at shows or events or on busy yards.1 Once the virus is reactivated the horse will shed virus into the environment possibly causing new outbreaks. This has the potential to affect the health of the whole yard.2 Unfortunately, there is no cure for EHV. Once a horse has the virus it is likely to remain a carrier for the rest of its life. Horses most at risk of EHV Moving and mixing horses with others increases the risk of spread of infectious disease.6 Competition and Riding Club horses are likely to be at increased risk not only because of their exposure to other horses at venues but also because the stress of travelling and competing can trigger reactivation of the virus in horses that have been previously infected with EHV.7 Horses at livery yards, especially those with new horses regularly coming on to the yard are also likely to be more susceptible so it is always best for newcomers to be quarantined and for other yard occupants to avoid all contact until the new horse has been confirmed as free of disease.7 Breeding studs and yards with pregnant mares can also be particularly vulnerable to outbreaks which can result in the rapid loss of large numbers of foals (abortion storms).8 How does vaccination help? Vaccination plays a pivotal role because it helps tip the balance in favour of the horse’s immune system.

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What are the signs of EHV? Your horse will need to be tested by a vet to determine whether the virus is present but signs of respiratory disease are similar to equine influenza and can include: 3,4 ›› Fever ›› Nasal discharge that goes from clear to thick and yellow ›› Weepy eyes ›› Swollen glands ›› Cough ›› Lethargy ›› Reduced appetite ›› No obvious signs but you may have noticed a consistent reduced performance.5

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Although vaccinated horses can still be infected with EHV, it significantly reduces the presence of the virus in the environment (viral shedding), the severity and spread of the respiratory disease and the frequency of abortion.8 Reduction in the incidence of EHV-1 abortion has been attributed to widespread vaccination in pregnant mares.6,9

Help - I think my horse may have EHV If you think your horse may have any symptoms of respiratory disease, it’s sensible to isolate them immediately and contact your Vet to discuss the next course of action. In most cases horses will make a good recovery from EHV respiratory disease, the prognosis is guarded for those with EHV neurological disease.1 If you take away just one message from reading this Reducing the risk factors for EHV 2,4,8 ›› Minimise stress: such as that caused by overcrowding, heavy parasite burdens, poor nutrition, climatic extremes, concurrent disease and mixing animals from different social groups ›› Ensure good biosecurity: avoid contact with other horses, don’t share equipment, bowls or stables ›› Practice good hygiene: humans can spread EHV indirectly via their hands or clothing if they have been in contact with an infected horse ›› Quarantine new horses ›› Isolate infected horses ›› Don’t mix unvaccinated horses with vaccinated ones

article let it be this: Choose to vaccinate and to give your horse the protection it deserves. Vaccination is easy and it’s been proven to be effective at reducing the risks of respiratory EHV and reduction in abortions. Speak to your Vet to book your horses’ vaccinations now.

www.horsedialog.co.uk/ equineherpes

References 1. Allen GP. Respiratory Infections by Equine Herpes Virus Types 1 and 4. International Veterinary Information Service. 2002. 2. Slater J. What is Equine Herpes Virus? Accessed August 2019. https://www.horsedialog.co.uk/ Health/WhatisEHV.aspx 3. Davis, E., Disorders of the Respiratory System, Eds Reed SM, Equine Internal Medicine. 2018, 313 4. Allen, GP. Epidemic disease caused by equine herpesvirus-1: recommendations for prevention and control. Equine Veterinary Education; 14(3):136-142. 2002. 5. Slater J. Equine Herpesviruses. Eds, Sellon DC and Long MT. Equine Infectious Diseases, Chapter 14. 2nd Edition. Saunders Elsevier, St. Louis, Missouri. 2014, 151-168. 6. Lunn, D. P., Davis-Poynter, N., Flaminio, M. F., Horohov, D. W., Osterrieder, K., Pusterla, N., & Townsend, H. G. Equine herpesvirus-1 consensus statement. Journal Of Veterinary Internal Medicine / American College Of Veterinary Internal Medicine, 23(3). 450-461, 2009. 7. American Association of Equine Practitioners. Risk-Based Vaccination Guidelines. Available at: www.aaep.org/-i-166.html. Accessed June18, 20: 8. Ivens P, Rendle D, Kydd J, Crabtree J, Moore S, Neal H, Knapp S, Bryant N, Newton JR. Equine Herpesviruses: A Roundtable Discussion. UK Vet Equine, July/Aug. 2019 9. Kydd J, Townsend H, Hannant D. The equine immune response to equine herpesvirus-1: The virus and its vaccines. Veterinary Immunology and Immunopathology 1, 2006;111,15-30. MM-16136

FIVE THINGS YOUR VET WISHES YOU WOULDN’T DO

anything to make the Vet’s job more difficult.

Here, Robinson Animal Healthcare take a look at five things your Vet wishes you wouldn’t do!

To help your Vet diagnose and treat your horse effectively, it is important that we as horse owners don’t do

Apply products to a wound If a wound is severe enough to require veterinary treatment it is important to not apply anything to the wound before the Vet has had chance to perform an examination. Products such as purple spray and wound powder can interfere with the colour of the tissue and any discharge making it difficult for the Vet to properly assess and treat the wound effectively, resulting in delayed healing and poorer prognosis. Remove penetrating objects If a wound has been caused by an obvious penetrating object that is still clearly visible in the wound, don’t be tempted to remove the offending object. The Vet might need to perform an x-ray prior to removing the foreign object to determine the exact location, angle and depth and if it is penetrating any vital structures. Removing an object that is embedded in a wound before the Vet arrives can hinder treatment and prognosis, not to mention running the risk of not completely removing the whole object.

Delay phoning the Vet Never be afraid to call your Vet for advice, even for something that seems insignificant, such as a small wound. Delaying calling a Vet can seriously affect recovery and healing time.