As outdoor animals, there are several infectious diseases that every horse is exposed to.  Wild animals, particularly bats and raccoons, are key reservoirs for rabies. During the warm months of the year, exposure to mosquitoes increases their risk to Eastern and Westernequine encephalitis. Tetanus, as well, is prevalent in the environment. Therefore, it is recommended every horse in the United States be vaccinated against these diseases.

In the mid-Atlantic region, there is also a high rate of exposure to Potomac Horse Fever (spread by snails and May flies), and West Nile Virus (spread by mosquitoes). These vaccines are strongly recommended in this area, in addition to the ones listed above.

Influenza and Rhinopneumonitis are vaccines that are risk-based. As these diseases spread horse-to-horse, horses are only at risk of becoming infected if they are in contact with horses from outside their farm (usually at shows, or lesson barns). We recommend these vaccines in those situations. These vaccines are also required for USEF and FEIshows.



Botulism is a disease caused by a spore found in the environment. While it is prevalent in areas such as Pennsylvania and New Jersey, rates in Maryland are low. We offer the botulism vaccine, and are happy to discuss if it is one your horse needs.


Intestinal parasites are of concern in all animal species. Our deworming strategy in horses had historically been to target Strongylus vulgaris, which could cause lethal colic. Fortunately, the advent of ivermectin and other dewormers has all but eliminated S. vulgaris from our equine population. A new challenge is emerging, however. Horse parasite populations are acquiring resistance to existing dewormers (similar to antibiotic resistance in bacteria), and no new dewormers are on the horizon. In an effort to preserve our dewormer effectiveness, we offer a strategic deworming program, where the horses who shed higher numbers of parasites are treated more frequently, and low shedders are treated only twice a year.