Many of you may not know the difference between Equine Herpesvirus-1 and Equine Herpesvirus Myeloencephalopathy. First of all, there are actually nine equine herpesviruses, but only three of them, EHV-1 (the one we're worried about), EHV-3 (which causes a venereal disease), and EHV-4 (which causes a non-fatal upper respiratory tract infection) pose a serious risk to domesticated horses.
The vaccine that we give for EHV-1/EHV-4 (Rhinopneumonitis) does not protect against EHM. There is no vaccination for EHM. Once affected with EHM, the standard form of care is simply supportive. Treatment may include intravenous fluid and anti-inflammatory drugs.
By about age two, many horses become infected with EHV-1 by contact with their dam. The virus is usually inactive, but may become reactivated by stress or contact with an affected horse. EHM is caused when the EHV-1 undergoes a mutation of the genome. [a very, very simplistic explanation!]
So what can we do about EHM? Interestingly, the literature I read strongly urges horse owners to NOT remove any horses from a site where a suspected case of EHM has been present until cleared by a veterinarian. Oops. That's what just happened. So what do we do now? Don't share tack, brushes, feed buckets, or any other communal items. Wash your hands and change clothes if you even suspect a horse might be ill. The disease is spread by horse to horse contact. DON'T allow horses to touch noses.
All the websites and blogs are reporting essentially the same thing. A case or two of the nuerologic version of Equine Herpesvirus-1 have been confirmed with a few other horses being treated as though they are positive. Most experts are recommending a quarantine period for animals suspected of being infected. The next few days should reveal a more complete picture.
For More Information:
- This is a brochure from the US Department of Agriculture that gives a very clear and easy to understand explanation of the Equine Herpesvirus. It's the most informative piece I've seen. You can access the file here, scroll down and download the pdf, or view the file in the window down below.
- This one is from the American Association of Equine Practitioners, click here.
- This one is from Equus, click here.
- This one was issued from the California Department of Food and Agriculture, click here.
- This one is from "Quarter Horse News", click here.
- This one is the National Cutting Horse Association's Facebook page, click here.