Alberta stands out as one of the few jurisdictions in North America in which horses are not routinely vaccinated against rabies. Arguments have always been that the incidence of rabies is much lower than in other regions, and there have been no reported equine cases of rabies in years, so the risk of infection would be so low as not to necessitate vaccination. The rabies vaccine must be administered by a veterinarian, another potential stumbling block to widespread vaccination of equines.
The rate of rabies in potential sources of infection within Alberta is the same whether we are considering a wildlife vector could infect a dog, a cat, or a horse. Yet rabies vaccination of our small animal companions is routine whereas vaccination of horses is almost non-existent. Although relatively rare, rabies is present in wildlife populations in Alberta, clinical disease should it occur is untreatable and (almost) invariably fatal, and a rabid companion animal or even horse can have very significant public health ramifications. Should we be revisiting this policy of non-vaccination of horses in Alberta?
How common is rabies in Alberta?
Alberta has not reported any equine cases of rabies in the past 10 years. In 2014, Alberta confirmed 4 cases of rabies, all in bats. Every year between 2004 and 2014, Alberta has consistently reported between 0 and 5 positive rabies cases per year, for a total of 25 positive cases in that time frame. Most of these infections occurred in bats, however in 2013 there was one case of rabies in a dog in Alberta, and in 2010 and 2006, there were rabies positive cats—one in Cremona in 2010, and one NW of Innisfail in 2006. Many of the most recent positive bat cases have been in the Pincher Creek area.
A 73 year old man died from rabies infection in Alberta in 2007, after being bitten by a bat. Bats have long, sharp needle like teeth that do not always leave an obvious mark, so detecting bat bites on animals, and therefore potential exposure, can be very difficult.
What would be the potential source of rabies virus for horses?
Any mammal can potentially be infected with rabies, but the most common wildlife reservoirs of the disease are bats, skunks, raccoons, and foxes. In recent years, most reported wildlife infections in Alberta have been in bats. Rabies has become well established in Canadian wildlife, although the main reservoirs vary geographically. Rabies in Canadian wildlife steadily increased up to the year 2000, then has decreased from 2000 to 2009 and roughly held steady since then. However, 30% of all confirmed rabies cases occur in bats and skunks in Ontario, Manitoba and Saskatchewan.
Saskatchewan represents an interesting rabies picture. That province has reported 1-3 positive EQUINE cases of rabies in 7 of the last 11 years. There does appear to be a higher prevalence of rabies in Saskatchewan compared to Alberta (for example, Saskatchewan reported 20 positive rabies cases in 2014 compared to four positive cases in Alberta), but it does serve to indicate that horses are very much susceptible to rabies infection and are commonly affected when there is rabies present in the surrounding wildlife. In total, from 2004-2014, Saskatchewan experienced 11 positive rabies cases in horses alone.
Is the vaccine a yearly vaccination?
Yes. Rabies is an excellent immunogen—that is, the body responds strongly to just a single dose of the vaccine and usually mounts a reliably effective immune response. Therefore, except in foals, initial vaccination usually involves just one dose and does not require a second dose in a matter of weeks. It is recommended to vaccinate yearly thereafter. Foals can be vaccinated as young as 6 months, although it is recommended to give them a booster 4-6 weeks later, then annually.
As mentioned above, however, this vaccine must be administered by a veterinarian. This is to ensure reliable proof of proper vaccination in case the animal is exposed to rabies, including proper vaccine handling, administration, and recording of the vaccination.
The fact remains that there has not been an equine case of rabies reported in Alberta in the past 15 years. However, as the example of Saskatchewan shows, horses are very much susceptible to the virus and are commonly infected when rabies is present in the environment. Saskatchewan currently has an apparently higher prevalence of rabies virus in wildlife species, but rabies cases in domestic animals (dogs and cats) have been reported in Alberta recently, and further have been reported close to the Calgary area. There is an effective, licensed vaccine for horses, and it is relatively inexpensive, however it must be administered by a veterinarian.
We at Burwash Equine Services wish to make you aware of the prevalence of rabies in our area, and the potential risk for your horses. The American Association of Equine Practitioners does recommend rabies vaccination as a “core” vaccination for virtually all horses, and we wanted to make our clients aware that we do offer this service. Please contact the clinic for more information and/or to request rabies vaccination with your horse’s yearly vaccines.