This is copied from another forum and all credit goes to Dr. Tanis MacDonald DVM
EHV-1 – What Do I Need To Know RIGHT NOW?
For the purposes of this post right this moment, I am not going to get into a lot of scientific details about Equine Herpes Virus 1 (EHV-1) – you can find the science with a Google search. What I am going to give you the down-and-dirty version of how it works and what you need to know RIGHT NOW to prevent this in your barn.
First, the EHV-1 virus has been around for a long time. This disease is nothing new. However, it is the kind of virus that mutates frequently. This makes it hard to target long-lasting vaccines toward the virus.
EHV-1 can cause 4 kinds of disease in a horse – but we are going to focus on the respiratory version and the neurologic version. In many horses that contract EHV-1 viruses, they spike high fevers, become lethargic, have clear runny noses and generally feel like crap. Many horses only get the respiratory version and clear the virus after a few days and have no further problems with it.
In some horses, and no one understands why they do this, the respiratory form can become the neurologic form. Literally, the virus gets into the spinal fluid and causes a myeloencephalopathy – a severe viral brain and spinal fluid infection. This infection is what causes the horses to become suddenly neurologic.
The EHV-1 virus is RIDICULOUSLY contagious. It spreads via nasal secretions, and horses can contract it by touching the nose of another horse, through the air or from simply being in a barn that was previously occupied by a horse that was shedding the EHV-1 virus.
The current outbreak has been linked to a cutting horse show in UT and linked cases are now popping up in several other states. As such, several vet school hospitals are closed or not seeing emergency patients, many horse shows are being cancelled, etc.
STEP 1 – STAY HOME!
The first step in prevention of EHV-1 is to take a deep breath, and STAY HOME. There is no such thing as an Emergency Horse Show. This is not the time to go visit your friends down the street with horses. This is not the time to load up and meet 20 different trailers at a trail ride and head out for the day. The BEST way to prevent EHV-1 exposure is to quarantine your horses and barn from other equine traffic.
If you have been in contact with horses associated with the Utah show, you should start to take temperatures on your horses twice a day. The fever spike is one of the very first signs that happens in horses. If your horse spikes a fever, you need to contact your equine vet IMMEDIATELY for further instructions and testing.
STEP 2 – VACCINATE
There is NO EHV-1 vaccine that is labelled for the prevention of the neurologic form of EHV-1. However, several are labelled for the prevention of the respiratory form. This is the “rhino vaccine” that your horse normally gets in its regular vaccine series. It is KEY to note that the rhino vaccines generally have a very short efficacy even under normal circumstances. If your horse is high risk, or has had exposure to horses or barns that are affected, even if your horse just had a recent “flu/rhino” vaccine in its spring series, it would be a good idea to consider boosting your horse with a rhino-only vaccine.
The two most effective rhino vaccines to use in the face of an outbreak are Rhinomune (modified live virus) or Pneumabort-K (killed vaccine).
Rhinomune vaccine should be used ONLY in non-pregnant animals because it is a modified live vaccine. It should be noted that there is a small chance of a horse developing colicky symptoms secondary to the vaccine administration, so monitoring the horse after the vaccine is important.
Pneumabort-K is a vaccine that is labelled for pregnant mares, so is definitely safe for them. It can also be used in stallions, geldings, and non-pregnant mares as well with no problems as an off-label use. It is a high-reaction vaccine, and often makes a lump in the muscle where it is given.
*Edit here to add Prodigy by Intervet Schering Plough to the list of high-antigen load vaccines that are useful in the face of an outbreak.
Again, the key here is to try to prevent the respiratory form of EHV-1 so that the horse doesn’t develop the neurologic form.
The reason these vaccines are the ones recommended is because they are the most potent vaccines against EHV-1 – they contain the most dead or modified live EHV-1 virus per dose. In the face of an outbreak, it is important to boost those antibodies hard and fast and these vaccines can do that. If you cannot get ahold of either of these, the third choice would be to reboost one of the normal Flu/Rhino vaccines that are on the market.
STEP 3 – IMMUNE BOOSTERS
The immune booster, Zylexis, is labelled for the treatment of the respiratory form of EHV-1. The idea is to help boost the horse’s natural immune system and make it stronger, therefore making it easier for the horse to fight the virus naturally. Zylexis is given on day 0, 2 and 9 as a IM injection.
Another immune booster is EqStim, which is similar to Zylexis only given IV instead.
STEP 4 – BE SMART
Again, to reiterate, stay calm and stay home.
Quarantine your barn from unnecessary horse traffic. Do not travel with your horse unless under emergency circumstances.
copyright Tanis MacDonald, DVM 2011
Now back to your regularly scheduled bitcher and moaner, ME! I have to agree completely that there is absolutely no show worth taking a sick horse too. I don't care if it's the fricking Olympics, if the horse is sick he stays home. On the other side of the fence is the healthy horse that can show, but shouldn't. If there is a contagious disease at any facility you are planning to go to, within the next 60 days, DON'T GO! You are not going to win enough prize money to pay vet bills or buy a new horse if your horse gets sick and dies. Stay home and spend some time brushing up and getting caught up on other stuff. Do not think for a second that your horse is safe and that it couldn't possibly happen to you. That's exactly what the people that have infected horses now thought and look how wrong they were! So for your sake and your horses, stay home and stay safe.