By Dr. Robert Hunter, DVM
Two-way..Four-way..how many ways should you go to keep your horse healthy and safe from infectious diseases? Your Sacramento vet should be consulted when deciding which vaccines to administer and when the best time is to take action. Many factors are considered when your vet makes a recommendation, and it may differ for each horse in your barn.
Your vet will consider your horse’s age, breeding status, travel plans, stable mates, overall health, and known outbreaks in your region before suggesting a vaccination regimen. Taking into consideration the entire environment in which your horse lives is equally important to understanding the seasons for mosquito-borne diseases.
April is the month to review your horse’s vaccination schedule and to be sure that they are protected from various forms of Encephalitis. Both Sleeping Sickness and West Nile are spread by infected mosquitoes, and their peak season in the Sacramento region is mid-summer through early fall. The vaccinations against these deadly diseases are most effective when given several months in advance (April through June).
3-Way Plus West Nile Vaccination Addresses Seasonal Outbreaks
Depending on the horse’s current health and use, I recommend as a starting point that a 3-way shot be given in spring. This combined shot addresses Eastern and Western Encephalomyelitis, Tetanus and West Nile. If your horse was vaccinated in January, a booster by the month of June would be appropriate.
Eastern Equine Encephalitis (EEE) is found primarily in the Eastern part of the United States and rarely is found in the Midwest and West. Generally speaking, EEE is found along the Eastern seaboard from New England to Florida. It generally kills affected horses–the case-fatality rate ranges between 75-100%. Since migrating birds are the carrier for this and other forms of Encephalitis, western-based horses are advised to protect against the disease.
Western Equine Encephalitis (WEE) is found in the Western part of the United States and is the form of encephalitis that is least fatal in horses. Research has shown that the case-fatality rate generally ranges between 20-50%. While many horses with WEE exhibit signs of “sleeping sickness,” some become agitated and excitable. Animals that survive an attack generally show gradual improvement within a few months.
Tetanus - Since the organism that causes Tetanus can be found in horse manure, the Tetanus vaccination is extremely important. When a horse’s wound comes in contact with the manure the outcome can be fatal without treatment.
West Nile (WNV) – The first signs of the disease will display between five and 15 days after the infected mosquito bites the horse. As is the case with WEE and EEE, there is no cure for infected horses because no specific antiviral agents have yet been identified that act upon WNV. The case-fatality rate is around 30% in horses.
For a complete list of vaccination schedules, visit the Hunter Stallion Station website at: http://www.hunterstallion.com.
Knowing which vaccines to give, and when, can make the difference between health, and even life or death for your horse. Be sure to check with your Sacramento vet to tailor your vaccination schedule to each horse in your barn. I will provide more detailed information on other recommended vaccinations in subsequent posts.
