Winter in this country is a beast. As I write this, we are into our 4th blast of snowy and cold weather already this fall (did I count right?), and it seems that winter is already well on its way to settling in. So a blogpost about proactive winter horse care may already seem a little past tense, but if you’re like me and living in denial that summer is already well past and fall quickly disappearing, you will have a few horse health care items to check off your list!

Many people have heard of PPID or Equine Cushing’s Disease, but it can be a difficult disease to fully understand. By reading this blog post you can better understand what PPID means, how PPID presents clinically, how we can diagnose PPID, and what we can do to manage our PPID patients.

Dr. Lindsay Rogers discusses topics of importance to the care of senior horses, including weight control and feeding, winter care, herd and housing management, and diseases that are more common in geriatric horses. She offers advice on monitoring and optimizing the quality of life for individual older horses, with lots of awesome examples from her own eccentric herd of equine seniors.

Dr. Alyssa Butters gives an update on the status of West Nile Virus and Rabies in Alberta, and gives current vaccine recommendations.

Dr. Doug Myers from Boehringer Ingelheim speaks about the importance of vaccines and discusses vaccine reactions. (Fall Seminar, part 1 of 4).

The theory of an intranasal vaccine for Strangles is that the site of entry and infection with Strangles is via the tonsils located in the nose and mouth.  If we stimulate immunity at these sites by introducing a vaccine directly to those tonsils, we can limit the propagation of the bacteria at its site of entry.  The Strangles vaccine most commonly used is a modified live bacterial vaccine, which is unable to replicate but mimics the immunity stimulated by a natural infection. However, its efficacy is dependent on an adequate amount of the vaccine reaching the tonsils deep in the head, so it must be administered via the nasal passageways.

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?

Equine Influenza Virus (EIV) is often cited as the most commonly diagnosed and economically important causes of viral respiratory disease in horses.  Therefore, the AAEP states that “all horses should be vaccinated against EIV unless they live in a closed and isolated facility.”  Like many other respiratory viruses, it produces fever, nasal discharge, and coughing.  So what sets this virus apart from other equine respiratory viruses?

  Potomac Horse Fever can cause very serious diarrhea, and other symptoms may include fever, laminitis, and colic.  It is caused by Neorickettsia risticii, a bacteria found in freshwater snails that is believed to be transmitted to horses via inadvertent ingestion of infected aquatic insects.  It is usually seasonal, seen most commonly in the hot summer months or early fall. If Potomac Horse Fever has occurred in a particular geographic area, it is likely that additional cases will occur in future years. However, vaccination against this disease has been controversial.  Evidence of protection against clinical disease is lacking, possibly because the vaccine may not stimulate a protective immune response, or potentially because multiple strains of the bacteria may exist, whereas only one strain is present in the available vaccine.

                This is a difficult question to answer, and there is little scientific data to guide recommendations.  It is very convenient to have all vaccinations given all at once to save time and money, and it is very commonly done with little adverse effects.  There are no studies examining the safety or efficacy of the vaccines when multiple different ones are administered together.  This does not mean they are not safe or not effective if given in combination, just that this has not been proven.  It does appear that there is a higher rate of adverse reactions if multiple vaccinations are given at one time, however, the overall rate of adverse reactions is still very low.  If your horse has experienced an adverse reaction in the past, it may be wise to split up his or her future vaccinations, both to decrease the risk of an adverse event as well as to determine if a particular vaccination is the culprit causing the horse to react.  If multiple vaccinations are given on the same date, it must be considered that modified live vaccinations should not be given close to the site of a killed vaccination, as the adjuvant in the killed vaccine may interfere with the activity of the modified live vaccine.  Seek your veterinarian’s advice if this is a concern.

         We get this question quite often, and it would be convenient to combine the treatments to save on an additional call fee.  However, we generally recommend against this for a few reasons.  One of the drugs we typically use in joint injections is a steroid anti-inflammatory such as triamcinolone or methylprednisolone acetate.  These are very potent anti-inflammatory agents, and can cause immune suppression even in the small amounts used in joints.  This means that the immune response to a vaccine could be dampened by the steroids injected in the joint, and the horse may not be adequately protected by the vaccine if it is administered at the same time as intra-articular injections.  Also, in the case of the intranasal Strangles (Strep equi) vaccine, we are very careful not to have contamination of any injection sites with the snorting of the vaccine after the horse is given this vaccine.  If this modified live bacteria is inadvertently injected, it can set up a nasty abscess and this would be particularly devastating if this infection were to occur in a joint.

Most horse people have heard of Strangles, and many have had the unfortunate experience of dealing with an outbreak.  The disease, sometimes referred to as “distemper,” is not new—it was first reported in 1251.  The disease is highly contagious.  Young animals (weanlings, yearlings, and other young stock) are particularly susceptible, however any age of horse can be affected.