April 2021 - Is Your Horse Protected Against These Disease Risks?
Written by courtesy of Valley Vet Supply • photo: Said Safri / Shutterstock.com
Thursday, 01 April 2021 20:11
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courtesy of Valley Vet Supply • photo: Said Safri / Shutterstock.com

Are you aware of the core and risk-based equine diseases that could be threatening your horse’s health?

Learn About Core Equine Diseases

Every horse deserves protection against the five core equine diseases, which include: Eastern equine encephalomyelitis (EEE) and western equine encephalomyelitis (WEE), Rabies, Tetanus and West Nile Virus.

Why do experts recommend horses be vaccinated against these five diseases? All horses can be exposed to wildlife and mosquitoes that transmit core equine diseases. Core vaccinations are recommended for all horses because the diseases are prevalent; highly infectious; have the potential to cause serious disease or death; pose a threat to human health, or are required by law. The core vaccination guidelines were created by the American Association of Equine Practitioners, the leading group of equine veterinarians.

Eastern and Western Equine Encephalomyelitis. Eastern equine encephalomyelitis (EEE) and western equine encephalomyelitis (WEE) are viral diseases that attack your horse’s nervous system. The risk of exposure to the virus varies from year to year with changes in the distribution of mosquitoes as well as birds and rodents that serve as virus reservoirs, but all horses are potentially at risk.

West Nile. West Nile virus causes inflammation of the central nervous system. Transmitted by mosquitoes, which feed on infected birds, horses are at the highest risk for contracting West Nile virus during peak mosquito season occurring July through October in the United States. Because the virus has been identified in the entire continental United States, as well as Mexico and Canada, all horses are considered at risk.

Rabies. This equine neurologic disease is caused by a virus in the saliva of infected animals, usually transmitted through a bite. Once inside the horse, the rabies virus travels up the nerves to the brain, where the disease progresses rapidly and is always fatal. As a zoonotic disease, rabies presents a risk of disease transmission to humans. Annual vaccination is critical to help protect horses and those who care for them.

Tetanus. All horses are at risk for developing tetanus, a potentially fatal bacterial disease caused by Clostridium tetani. Present in the intestinal tract and feces of horses, other animals and humans, the bacteria can be abundant in the soil. Bacterial spores can survive in the environment for years, creating a constant risk for horses and people.

Learn About Common Risk-Based Equine Diseases


If your horse falls into any of the categories outlined below, he may benefit from vaccinations against risk-based diseases, such as equine influenza, equine herpesvirus (rhinopneumonitis), leptospirosis, strangles and Potomac horse fever.  

•    Younger than 6 years old
•    Older than 15 years old
•    Stabled in a boarding barn
•    Travels off-property
•    Stabled with horses that travel off-property

Venezuelan equine encephalomyelitis (VEE). Like core equine diseases EEE and WEE, VEE is also transmitted by mosquitoes (and sometimes other blood-sucking insects) to horses from wild birds or rodents. VEE mortality rates can reach up to 80%. The disease occurs in South and Central America, and although VEE has not been diagnosed in the United States for more than 40 years, disease risks remain, especially for competition horses.

Equine influenza. Equine influenza is one of the most common respiratory diseases in horses, spreading by aerosol transmission (coughing or sneezing) from horse to horse in distances as far as 50 yards. Like humans with a cold, horses may experience dry cough, nasal discharge, fever, depression and loss of appetite.

Equine herpesvirus. Equine herpesvirus is most commonly seen in weanlings, yearlings and young horses entering training or those exposed to other horses through boarding or transport. Equine herpesvirus poses severe risks, including respiratory infection as well as abortion, birth of weak, nonviable foals, and can lead to sporadic neurologic disease.

Leptospirosis. Horses can become infected with leptospirosis when exposed to Leptospira bacteria in urine from contaminated soil, bedding, feed and water. The bacteria penetrate the mucous membranes of the eyes or mouth or enter through skin abrasions. Once in the bloodstream, leptospires can concentrate in the kidneys, be shed in the urine and cause serious medical problems. Additionally, Leptospirosis outbreaks may be related to rainfall. Heavy rainfall can increase the risk of leptospiral abortions in pregnant mares by as much as 3.7 times, with losses as high as $4.2 million for the Thoroughbred breed alone.

Strangles. Strangles in horses is caused by the bacteria Streptococcus equi (S. equi). It is a highly contagious upper respiratory disease most common in young horses. It also has several potentially fatal complications and the capability to cause persistent infections in populations of asymptomatic carrier horses. Strangles can spread quickly and easily through a barn or herd because of its ability to be transmitted through direct animal-to-animal contact or by objects such as bridles, buckets or human hands.

Potomac Horse Fever. Potomac horse fever can impact horses of all ages, resulting in mild colic, fever and severe diarrhea. The disease also can cause abortion in pregnant mares. The disease is seasonal, occurring between late spring and early fall in temperate areas, with most cases in July, August and September with the onset of hot weather.

Help protect your horse through vaccination against core and risk-based diseases. Speak with your veterinarian to learn more.

Find trusted vaccines available with quick shipping and careful handling from www.ValleyVet.com.