Zoonotic Diseases Affecting Horses and Humans


Veterinarian with horse owner

Horses can be impacted by several different diseases and illnesses. Preventative steps are critical to keeping your horse healthy. But what if your horse does become ill – can the disease be transmitted to you?

Every horse person needs to know about zoonotic diseases (an animal disease that can be transmitted to humans) for their own safety as well as that of their families and employees. These diseases, their clinical signs and advice are discussed in this brochure. …

Vesicular Stomatitis

Kathy Anderson, Extension Horse Specialist, University of Nebraska

Vesicular stomatitis is a viral disease which affects horses, cattle, swine, and occasionally sheep and goats. Additionally, numerous species of wild animals including deer, bobcats, goats, raccoons and monkeys are susceptible. The virus causing vesicular stomatitis can also infect handlers of infected animals.

Vesicular stomatitis most commonly occurs during warm months in the Southwest region of the United States, particularly along river ways and in valleys. Recent outbreaks in the Southwest …

The Role of Nutrition in Horse Colic and Laminitis

Laminitis is inflammation within the sensitive laminae of the feet. It can occur for many reasons, but as a nutritional problem it is commonly linked to grain-rich diets, ingestion of too much rich pasture, and obesity. Grain overload or a diet rich in high-carbohydrate feed (grain or lush pasture) initiates a series of metabolic and endocrine (hormone) disturbances in the body. A diet abundant in carbohydrates upsets normal intestinal bacteria, allowing more endotoxins from harmful bacteria to be absorbed into …

Bacterial Diseases of the Horse


Craig Wood, University of Kentucky

Strangles is a highly contagious upper respiratory infection in horses. The cause has been identified as a bacteria. The disease has a low mortality rate, yet the economic ramifications due to long recovery periods can be great. The disease is contracted through environmental contamination, nasal discharge, or direct contact with infected animals.

Clinical Signs
1. high fever of 103 to 106 F
2. loss of appetite
3. a moist cough
4. clear nasal discharge that

Encephalomyelitis in horses

Ashley Griffin, University of Kentucky

Equine encephalomyelitis, also called “sleeping sickness,” is an infectious disease that affects the brain of the horse. Three strains have been identified: Eastern, Western, and Venezuelan. The mortality of the three strains runs from moderate to high. The Eastern strain occurs more frequently and has the highest mortality rate.

The cause of encephalomyelitis is a virus. Reservoir hosts include birds, reptiles, and rodents. The mosquito acts as the vector, transmitting the virus from the …

Equine Infectious Anemia (Coggins’ Disease)

Ashley Griffin, University of Kentucky

Equine infectious anemia (EIA), or swamp fever, is a viral disease that occurs worldwide. The disease is usually spread by horse flies biting an infected horse, then biting a healthy horse. The disease can also be transmitted by the use of nonsterile needles and blood-contaminated surgical instruments.

Clinical Signs


1. high fever
2. labored breathing
3. pounding heartbeat and exhaustion
4. anemia.


Horses that recover usually remain carriers of the disease. The death rate is low.…

Equine Protozoal Myeloencephalitis (EPM)

Craig Wood, University of Kentucky

The organism Sarcocystis neurona, a single-celled animal, can cause equine protozoal myeloencephalitis (EPM), a neurological disease that can affect equines of any age, sex, and in any location throughout the United States. The parasitic cycle involves birds eating plants and other animals of prey that carry the sporocysts of the organism. The opossum then eats birds killed by the effects of the disease. The organism reproduces sexually in the opossum and is passed …

West Nile Virus in Horses

West Nile Virus (WNV) is a mosquito-born virus that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord) in humans and horses. Mosquitoes that acquire it from infected birds transmit the virus. This virus was first discovered in the United States in New York in 1999 and has quickly spread throughout the U.S. The virus was found in dead birds as far west as Missouri and eastern Iowa in the …

Disease: Equine Influenza

Equine Influenza is a highly contagious respiratory disease, which spreads rapidly among susceptible horses. It is rarely fatal except in young horses. The incubation period of influenza is ~1-3 days. Clinical signs begin abruptly and include high fever (up to 106 degrees F [41.1 degrees C]), serous nasal discharge, and coughing that is dry, harsh, and nonproductive. Depression, anorexia, and weakness are frequently observed. Clinical signs usually last less than three days in uncomplicated cases. Cough develops early in the …

Equine Viral Rhinopneumonitis in horses

Ashley Griffin, University of Kentucky

Equine viral rhinopneumonitis (EVR) produces an acute respiratory catarrh, which is inflammation due to excessive discharge or buildup of mucus in the throat and nose. The Type I strain of EVR is the most common virus found in horses. Transmission of EVR occurs with direct or indirect contact with virus-laden nasal discharge, aborted fetus, or placenta. 

Clinical Signs


1. congestion and clear nasal discharge
2. mild to server ataxia or paresis (slight of incomplete paralysis) of …