Vaccination Update
Filed under: Articles, Bacterial Disease, Vaccination, Viral Disease
Tawna Backman Purcell, DVM
printer friendly PDF format
Choosing which vaccinations to use to provide protection for your horse largely depends on what part of the country you live in as a nationwide protocol doesn’t exist. The AAEP (American Association of Equine Practitioners) publishes a list of guidelines for veterinarians to use while developing vaccination protocols for their specific area. Within these guidelines there is a list of core vaccines that all horses should get regardless of their location. Veterinarians then choose which additional vaccines to use based on the risk (exposure, age, sex, use, location) and consequence (severity, possible transmission to humans) of disease within their community and the effectiveness or possible adverse affects of the vaccine.
Here in mid-Missouri we recommend vaccinating all horses for the core vaccines of EEE (Eastern Equine Encephalomyelitis), WEE (Western Equine Encephalomyelitis), Tetanus, West Nile Virus, Equine Influenza, Equine Herpes (Rhino) Virus, and Rabies. We also recommend vaccinating against other pathogens should the horse be in an area of risk, such as frequent traveling and co-mingling with unfamiliar horses. These vaccines include Equine Viral Arteritis, Streptococcus equi (Strangles), and Potomac Horse Fever. Even within a community the age of the horse, sex, pregnancy status and individual farm needs will determine which vaccines are given at which time.
Equine Influenza generally affects horses between 1-5 years of age, although all horses can potentially be infected. The vaccine should be given to horses that travel extensively to areas of an unknown horse population (shows, breeding farms) or live on farms with constant horse turnover. Depending on the risk of disease occurrence, the stress level of the horse and the product to be given the vaccine can be given once up to 4 times per year.
Potomac Horse Fever (PHF), caused by the agent Neorickettsia risticii, is typically most prominent in the Virginia/Maryland area around the Potomac River. It was identified in the St. Louis area this summer. PHF is a rare occurrence, especially in Missouri, however the unusually wet summer and flooding allowed for the perfect conditions.
Equine Viral Arteritis (EVA) is a virus that causes mild respiratory disease and abortions. The vaccine is primarily given to breeding stallions or mares that are going to be bred to an EVA carrier stallion.
Streptococcus equi is the bacterial name for Strangles. This vaccine is available in two forms and is usually given to those horses on a farm with a history of Strangles infection or if a horse travels to a known area that has or has had strangles outbreaks. There are some adverse effects that are rarely seen with this vaccine, so it is best to discuss those effects with your veterinarian.
Equine Herpes Virus 1 and 4 cause reproductive and respiratory ailments as well as neurological disease. EHV 1 can cause all three conditions and can be a devastating disease, while EHV 4 causes mild to moderate respiratory signs and rarely abortion. Vaccination requires a booster and depending on the risk of coming into contact with the disease, boosters ever 3months to one year. Pregnant mares should be vaccinated on the 5, 7 and 9th month of pregnancy.
Recently the AAEP added the rabies vaccine to the core vaccination list. Rabies is a fatal disease to unvaccinated horses and potentially fatal to unvaccinated humans who might come in contact with rabid animals. In 2008, one equine case of rabies was identified in Missouri and many more in the bat and skunk populations. When dealing with such a devastating disease we feel vaccination is the best safety policy for both you and your horse.
It should be mentioned that vaccinations may not completely prevent a horse from contracting a disease; however vaccines will reduce the severity of disease as a whole should the horse come in contact with it. Monitoring movement of horses on and off farms, preventing overcrowding, good vaccination/health record keeping and cleanliness should all be taken into account for overall disease prevention on both small and large farms. Vaccinations and boosters, when applicable, in combination with overall good husbandry are essential to insure the maximum benefit.