Due to the rapid spread of a very aggressive strain of the neurological form of Equine Herpes Virus (EHV-1), with four deaths and multiple confirmed cases, The FEI has cancelled international events in 10 countries on the European mainland with immediate effect until 28 March 2021. The strain originated in Valencia, Spain and has been confirmed as the source of a further three outbreaks in Europe.
EHV-1 is a contagious disease that can be spread through direct and indirect contact, with the virus surviving in the environment for several weeks. Clinical signs include a high temperature, coughing, nasal discharge, lethargy and loss of appetite. Severely affected animals can display neurological symptoms, and pregnant mares can also suddenly and unexpectedly miscarry their unborn foal.
It is thought that subclinical EHV‐1 infections are common in horses (i.e. horses that are infected but show no symptoms) resulting in frequent spread and a high risk of exposure particularly in open horse populations subject to stress, introduction of new animals and mixing at events/competitions. Reactivation from this subclinical state with shedding of virus and transmission to susceptible hosts, is a defining feature of herpesviruses and is very likely to play an important role in EHV‐1 disease outbreaks.
Vaccination against EHV is important because it helps to prime your horse’s immune system to respond faster and more effectively to ward off disease.
EHV vaccination helps reduce the severity and spread of the respiratory disease and frequency of abortion disease. There is no EHV-1 vaccine licensed for use to prevent neurological disease. Reducing the spread of Equine Herpes Virus through management and vaccination is key to disease control. We do not advise commencing EHV-1/-4 vaccination in animals that may have been exposed to EHV-1/-4 and/or are undergoing isolation and screening as it may lead to the animal suffering a more severe case of the disease. It can safely be given to a horse who has previously come in contact with the virus, as long as the animal is not showing clinical signs or incubating the virus at the time. The vaccine won’t be as effective when given to a carrier as it would be if given to a horse which hasn’t come in contact with the virus.
The primary course consists of 2 vaccinations 4-6 weeks apart. Following completion of the primary course, booster vaccinations should be administered every six months.
The current EHV outbreak serves as a reminder of the importance of biosecurity, vaccination and having plans in place for protecting horses travelling to, and returning home from, events.
The infographic below from The British Horse Society demonstrates the simple steps we can all take to prevent the spread of infectious disease.