22/04/2024
Hope this clears up some of your questions and worries.
Thanks Mayes and Scrine
𝐄𝐪𝐮𝐢𝐧𝐞 𝐇𝐞𝐫𝐩𝐞𝐬 𝐕𝐢𝐫𝐮𝐬 - 𝐄𝐇𝐕-𝟒
As some of our clients may already be aware, a case of EHV-4 has recently been diagnosed in the Surrey area. We hope this post provides some useful information about the virus, and sensible precautions all owners can take to minimise the risk of transmission.
𝐖𝐡𝐚𝐭 𝐢𝐬 𝐄𝐇𝐕?
The Equine Herpes Virus is a common DNA virus that most horses throughout the world will have already been exposed to, most often without displaying any serious symptoms. Of the four main types, EHV-1 and EHV-4 are most common in the UK.
EHV-1 can cause various types of symptoms in horses - respiratory, neurological and can cause abortion in pregnant mares.
EHV-4 most commonly causes non-fatal upper respiratory tract disease in young stock. However, it has more uncommonly been associated with abortion, and more rarely, with neurological disease. Adult horses are more likely to act as carriers of the virus: spreading it without showing clinical signs.
𝐖𝐡𝐚𝐭 𝐬𝐲𝐦𝐩𝐭𝐨𝐦𝐬 𝐦𝐢𝐠𝐡𝐭 𝐦𝐲 𝐡𝐨𝐫𝐬𝐞 𝐬𝐡𝐨𝐰?
Common symptoms: fever (a temperature of above 38.5C), lethargy, lack of appetite, nasal discharge, cough
Less common symptoms: abortion
Rare symptoms: neurological signs (wobbling, loss of coordination)
𝐌𝐲 𝐡𝐨𝐫𝐬𝐞 𝐡𝐚𝐬 𝐬𝐲𝐦𝐩𝐭𝐨𝐦𝐬 - 𝐰𝐡𝐚𝐭 𝐝𝐨 𝐈 𝐝𝐨?
- Contact your local veterinarian who may wish to perform a nasopharyngeal swab or blood test.
- Monitor your horse twice daily, including taking their temperature twice a day.
- Isolate your horse from direct and indirect contact with other horses.
A nasopharyngeal swab should be repeated at the end of the isolation period to check for viral DNA - only if this is negative should the horse be released from isolation.
Ideally, a voluntary yard lockdown should be implicated should a case be diagnosed. This can be lifted 28 days following the cessation of clinical signs alongside a negative swab.
𝐇𝐨𝐰 𝐝𝐨𝐞𝐬 𝐭𝐡𝐞 𝐯𝐢𝐫𝐮𝐬 𝐬𝐩𝐫𝐞𝐚𝐝?
- Direct nose to nose contact
- Airborne (currently it is unknown exactly how far the virus can spread in this way)
- Indirectly via physical objects (clothing, tack, grooming equipment etc.)
𝐒𝐡𝐨𝐮𝐥𝐝 𝐈 𝐯𝐚𝐜𝐜𝐢𝐧𝐚𝐭𝐞 𝐦𝐲 𝐡𝐨𝐫𝐬𝐞 𝐚𝐠𝐚𝐢𝐧𝐬𝐭 𝐄𝐇𝐕?
EHV is given as two vaccines, the second given 4-6 weeks after the first. It then needs to be given on a six monthly basis.
The vaccine reduces viral shedding, so lowers the risk of horses transmitting EHV to each other. However, for this to be effective at least 70% of the yard needs to be vaccinated - there is limited benefit in vaccinating just one horse!
There is no vaccination that will prevent the neurological symptoms – in fact, if a horse already has been exposed to EHV there is evidence to suggest that then vaccinating them can increase the risk of them developing neurological symptoms.
𝐇𝐨𝐰𝐞𝐯𝐞𝐫, vaccination does protect against all strains, a month after the 2nd vaccination. Vaccination of pregnant mares at 5/7/9 months to prevent abortion is normal practice at many large studs. Again, this relies on herd protection, and it is important to consider that like all vaccinations, the act of vaccinating itself can (rarely) cause abortion. As a result, vaccination needs consideration and application to the individual situation, and we would recommend discussing this with your veterinary surgeon.
Practicing good biosecurity measures is essential to preventing the spread of any contagious disease, not just EHV, and we would always recommend clients prioritise this.
Should you have any questions regarding biosecurity, EHV, or vaccinating against the virus, please contact the practice for veterinary advice on 01306 628222 or via [email protected] .
