Speaking for the Horses: Why We Vaccinate By: Dr. Matt Fehr, Animal Medical Center
Generally when I write articles such as this, I draw from my day to day experiences in veterinary practice for inspiration, and this one is no exception. A recent experience got me to thinking about why we vaccinate our horses. In general, the very basic reason why we vaccinate is to keep them from getting sick. We are trying to prevent them from developing the diseases that we vaccinate against. But is that it? Is preventing them from being sick the only reason? I will admit that keeping your horse healthy is the number one reason you vaccinate it. However, if we broaden our perspective a bit, we can consider the entire population of horses that our individual horse comes into contact with. We constantly talk about population medicine when we talk about the cattle we watch after every day, but we probably don’t spend enough time focusing on the entire horse population. For example, if you have a non-vaccinated horse, and you take that horse to a roping on a weekend and he contracts an influenza virus, then you bring that horse back to the yard and he becomes very ill. Now, your sick horse is penned with, or in close proximity to, every other horse in the yard. Hopefully the other horses are all vaccinated, but even a vaccinated horse can succumb to disease when faced with a high enough pathogen load. So now not only is your horse sick and possibly off work, but so are several others. Thus we are losing productivity as well as spending money treating multiple animals and possibly extra preventative measures to attempt to keep even more horses from getting sick. We could discuss an attempt at eliminating some of the diseases from the entire population as we have essentially done with diseases such as polio in people and brucellosis in cattle…….but I fear there are too many reservoirs in the wild animal populations that will make that quite impossible. Viruses such as West-Nile being spread by birds and rabies being able to infect any mammal, force elimination out of the realm of possibilities. The other “outside the box” reason for vaccination, and the one that stimulated this article, is prevention of zoonosis. I was recently called to look at a horse that had been down for two days. Upon arrival at the farm, I went straight into my normal examination as I would any other horse on any other day. I didn’t stop to put gloves on (as I was trained to do in school) for that “just in case” chance that the horse
had something I could contract. It was actually not until I was discussing the case with an internist friend of mine that rabies was put into my train of thought. Many explicit curse words went through my head as I thought about the possibility of this horse having rabies. There was no known rabies vaccination in this particular horse’s history and there were several people who had been in contact with the horse since it had become sick. Long story short, the horse died within two days and then tested positive for rabies. (Insert more explicit curse words.) Being a veterinarian, I have previously been vaccinated for rabies and we routinely check our titers and receive booster shots as needed. My post exposure treatment consisted of two shots, three days apart. Not terrible in the grand scheme of things, but they were costly and who likes shots? Not this guy. However, the others who had been exposed to the horse did not have it quite so easy. They each received a series of 4-6 shots as well as a dose of IV IgG, which I was told would probably cost in the neighborhood of $8-10,000 each. Why am I telling you all this? Because the entire incident could have been avoided by simply vaccinating the horse. Rabies is one disease that is nearly 100% preventable. The vaccine is considered very protective and very successful at preventing the disease. In addition, if you contract rabies and become clinically ill, it is nearly 100% fatal. Essentially, you get rabies and you die. West Nile is another zoonotic disease that we routinely vaccinate our horses for. Although it is not transmitted directly from the horse to a person, if your horse has it and a mosquito feeds from that horse then feeds on you, you get West Nile. West Nile is not nearly as fatal as rabies. Although, those I have known that contracted it, said they sometimes wished they would die because the disease made them so miserable. In closing, I highly encourage you to keep your horses up to date on their vaccinations, not just to protect them, but to protect surrounding horses as well as yourself. I’m sure you have heard the phrase “an ounce of prevention is worth a pound of cure”. This is a true statement! Treating a horse (or group of horses) for diseases that are preventable is much more costly than vaccinating them, not only in money, but performance, stress and potentially life. pacdvms.com 17
