Vaccines prevent horse fatalities

With the lengthening of days and promise of warmer weather, it’s the time of year to formulate and implement an appropriate vaccination program for horses before mosquito and horse competition seasons.

Most horse owners are familiar with the three-way vaccine, which is designed to protect horses against eastern and western equine encephalomyelitis viruses and tetanus. Mosquitoes transmit the two viruses to horses and people.

Tetanus is caused by a bacteria found in soil. It causes infection in open wounds and other skin defects. We all know how accident-prone horses can be. Even small nicks and scratches can permit the bacteria access to the body and the chance to multiply.

This bacteria causes toxins that make muscles stiffen. It is difficult and expensive to treat, although most cases are fatal.

West Nile Virus has become a standard component to most horse owners’ vaccination protocol. They should read the vaccine labels carefully to ensure this important pathogen is included.

Not all horses need vaccination against strangles. Horses that have limited contact with strange horses are at lower risk. They may not leave their homes, are in isolated herds with no new horses being introduced or live alone.


The bacteria that causes strangles is transmitted by direct contact or contaminated objects such as bits, water buckets and snot rags.

It is no longer valid to infect horses with strangles while they are young in an attempt to prevent severe disease later on and protect them for life. Vaccination and reduced exposure are the best ways to prevent this disease.

Equine influenza and equine herpes virus vaccines should also be added to the vaccine plan for horses that have increased contact with other horses.

Horses should be routinely vaccinated for rabies because it is a universally fatal disease and can also kill people. Contact between horses and rabid animals often goes unnoticed until clinical rabies develops.

Your veterinarian may recommend vaccination against anthrax and Potomac horse fever depending on your area and risk.


Intranasal vaccinations can be tricky to administer and require a bit of finesse, but generally they promote better local immune responses, which translates into better protection.

Injectable vaccinations stimulate antibodies in the blood stream, which is important for viruses such as West Nile and rabies. Intranasal vaccines stimulate antibodies on the surface of the inner nasal passages, which is where pathogens such as strangles gain access. Having the protection where it is needed can stop clinical disease in its tracks.

Most vaccines need to be kept cool before administration. Always change needles between horses. Intranasal vaccines must never be injected because it can cause severe, sometimes fatal reactions.

If your veterinarian is sedating your horse for other routine care such as dental floating or sheath cleaning, it is also a great opportunity to administer vaccines.

Alternatively, prepare for intranasal vaccination by desensitizing the horse to having the inside of its nostrils touched by first using your fingers and then the plastic tubing from the vaccine delivery system. Incorporate food rewards. Then draw up the vaccine, place the tube in the nostril and slowly push the plunger. Follow with a treat.


Injectable vaccines should be given in the neck muscle. Preparation and training will allow you to administer intranasal and injectable vaccines in subsequent years.

Dr. Jamie Rothenburger is a veterinary pathology resident at the Western College of Veterinary Medicine, University of Saskatchewan.