With the global increase in equine travel, as well as large populations of horses in close contact with one another, proper vaccination protocols are as important as ever, particularly in the US.
Veterinarian Kathleen Timmins, of Palm Beach Equine Clinic in Wellington, Florida, says she is often asked why proper equine vaccination protocols are imperative for all horses, and her answer voices directly to the welfare of the horse.
“You could save your horse’s life!” she said. “It is really important from an infectious disease standpoint, but also for mosquito-born diseases or rabies; these are diseases that are life-threatening for lack of a $25 vaccine.”
Vaccinations: What to use and when
According to Timmins, recommended vaccination protocols vary by vaccine and by the location of the horse, but the core group of vaccines is relatively standardized. As a rule, US horses should receive vaccines to prevent against mosquito-born diseases like Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), and West Nile Virus twice a year. Equine Encephalitis is characterized by the swelling of the brain in an infected horse, while West Nile Virus infects the central nervous system and may cause signs of Encephalitis, including those ranging from fever to weakness and paralysis of the hind limbs.
“Vaccinations against mosquito-born diseases become very important in south Florida because we have mosquitoes year-round,” Dr Timmins said. “As you go further north, owners may sometimes choose to vaccinate against those only once a year.”
Included in the twice-a-year vaccination program is a Flu/Rhino dose. The Flu vaccination prevents the illness in horses much the same way it does in humans, while the Rhino vaccine is key in helping to prevent the Equine Herpesvirus (Rhinopneumonitis). Equine herpesvirus type 1 (EHV-1) and Equine herpesvirus type 4 (EHV-4) most commonly result in respiratory disease in horses and can progress to neurological disease.
East and West Equine Encephalitis, West Nile, and Flu/Rhino can all be administered as a combination vaccine requiring only one injection.
In addition to vaccinations given twice a year, annual vaccinations include those to prevent Potomac horse fever, a potentially fatal illness that affects the digestive system and is caused by the intracellular bacterium Neorickettsia risticii; Strangles, a bacterial infection of the upper respiratory tract; and Tetanus, an acute, often fatal disease caused by the bacteria Clostridium tetani found in soil.
Much like the vaccinations administered to humans, the companies that produce the vaccines are in constant transition, adapting each vaccine to the most common strains to ensure the most accurate prevention of disease.
The role of the horse show
To combat the rise of infectious disease outbreaks, many show organizers have taken a proactive step to reduce the spread of disease by developing vaccination requirements for the show grounds. This is a step towards preventing disease as an organized community, according to Timmins.
“No one wants sick horses,” she said. “All horse show organizers can do is put the requirements out there and hope that people comply and that they understand why vaccinations are so important.
“When a horse pops with a fever at a show everyone is alarmed,” continued Timmins. “If proper vaccination protocols are followed, it is easier for us to figure out why that horse has a fever and treat them quickly and appropriately.”
There are occasional cases of horses reacting negatively to certain vaccinations, making a regular schedule difficult. After receiving a vaccine intramuscularly, some horses experience local muscular swelling and soreness or signs including fever, anorexia, and lethargy. Severe reactions such as anaphylaxis can also occur in rare, extreme cases.
According to Timmins, there are procedures in place to help keep horses that suffer reactions on a systematic vaccination plan without threatening their health or competition schedules.
“What I will do first is break up the vaccinations so we can figure out which one is bothering the horse,” Timmins said. “Then sometimes all it takes is a change in the vaccine company because the particular horse is reacting to their preservative or their carrier. Veterinarians can also pretreat with a nonsteroidal anti-inflammatory drug to avoid really bad reactions. Finally, there is always an option to administer intranasal vaccines rather than using an injectable.
“Very few horses have severe reactions to vaccines and for the most part, the horses traveling to shows are part of a young and healthy populations,” Timmins said.
As the winter horse show season continues throughout the US, horse health must be a priority and vaccinations are a simple way for the equine community to do their part.
“Vaccinations are an easy and relatively inexpensive way to prevent infectious disease outbreaks, and keep our horses healthy and safe,” she said. “There’s just no reason not to vaccinate.”