There are several different strains of EHV that can infect horses, the most important being EHV-1 and EHV-4. Both viruses can cause respiratory disease (characterised by an elevated temperature, cough, and nasal discharge), but EHV-1 can also cause abortion in mares and, rarely, neurological disease. Respiratory disease caused by EHV is extremely common in the UK (up to 90% of horses will be infected as youngsters), and in many cases infection by EHV-1 and EHV-4 causes only very mild clinical signs.
The best way to protect against EHV is to have good yard management such as reducing overcrowding, isolating sick horses etc., and having effective biosecurity protocols for new arrivals.
Vaccination can help reduce the severity of respiratory disease and instances of abortion. It also helps to reduce the amount of infective virus that is shed to other in-contact horses, reducing the risk of outbreaks.
Vaccination is particularly recommended for racehorses and pregnant mares. In addition, horses that are likely to benefit from vaccination are:
• Competition horses i.e. horses which travel away and have contact with other horses and/or shared stabling.
• Horses in livery yards where horses regularly come and go.
• Horses in venues where equestrian sports and disciplines take place.
Vaccination is most effective when an entire group of horses is vaccinated e.g. all horses on the yard/premises. However, where this is not possible or a viable option, vaccination of individual horses can help to reduce the severity of clinical signs and reduce shedding of the virus.
Unfortunately, there is no vaccine available currently that is effective at preventing the neurological form of EHV-1.
If you would like to learn more about EHV, check out the article below or give us a call and speak to one of our vets about prevention and vaccination.