In 2008, the American Association of Equine Practitioners (AAEP) published updated vaccination guidelines for horses.  One of the changes from the previous set of guidelines was the inclusion of rabies as a core vaccine (meaning every horse should receive it).  There was lots of discussion about this at the recent AAEP Annual Convention in San Diego, CA.

Some veterinarians don’t like the idea of vaccinating every horse against rabies.  Just like veterinarians and owners of dogs and cats who are concerned about over-vaccination in these species, the same concerns exist in equine medicine.  Equine rabies vaccines are not approved for use every three years like some canine and feline vaccines, so they still need to be given every year until someone can determine for how long a vaccinated horse is protected from infection.   Furthermore, there has never been (to my knowledge) a case of human rabies due to transmission from a horse.  These are all valid points, but there are also a lot of reasons why including rabies as a core vaccine for horses is very good idea:

• Rabies is a very deadly disease, in both animals and people.  To some owners, their horse is every bit a part of their family as any dog or cat could be.  To other owners, their horses represent a great investment, and part of their livelihood.  Even if the risk of disease in horses is low, protecting them is safe and easy, so it just makes sense.  As the saying goes, an ounce of prevention is worth a pound of cure, but when there is no cure and prevention is so simple… you do the math.
• Rabies vaccination is extremely effective in horses, producing an excellent immune response even with a single dose.  It does not require complex adjuvants that some other vaccines need to stimulate the immune system, which also makes it less likely to cause an abnormal vaccine reaction.
• Rabies is not a seasonal disease like many of the respiratory viruses or insect-borne diseases (e.g. West Nile) for which horses are also typically vaccinated.  Rabies boosters only need to be given once a year, so this can be done during a time of year when no other vaccines are required, if there are concerns about giving too many vaccines at once.
• Horses live outside and in barns.  Most are far less supervised than dogs and cats, but even these animals are at risk of rabies exposure.  A rabid animal could easily be "brave" enough to attack a horse, even though it normally wouldn’t.  Bats can also easily get into and out of many barns – you may never know one was there, and finding a bite mark from a bat on a horse would be like looking for a needle in a haystack, but that’s all it takes to transmit the virus.  So it makes sense to give your horse added protection by vaccinating it.
  
• Rabies in horses may not look like rabies at first.  One of the most common early signs is actually colic.  A rabid horse that looks like a colic may expose the people who are trying to look after it before they realize what the horse has.  In other horses the signs may be recognized too late, like the rabid horse that was found at the Missouri State Fair earlier this year, that resulted in exposure of many people.
• While rabies transmission from horses to people has not been documented, rabid horses have killed people, particularly horses that develop the "furious" form of rabies, which can cause them to become very violent.

For more information on rabies, see our rabies archive or the information sheets available on the Worms & Germs Resources page.  For more information on rabies in horses specifically, visit our sister site, www.equIDblog.com.