HORSE SICKNESSES
A note from Dr. Roberta Dwyer
Do horses get rabies?
Can you get the flu from your horse?
What horse diseases can you catch?
Do you know the answers to these questions? With certainty?
Many people do not know that horses can contract rabies from a rabid animal bite and therefore be a threat to human health. Rabies is likely the most commonly known zoonotic disease, which is one that can be transmitted between animals and people. Other diseases common to horses and people may have the same name but are not transmissible (or zoonotic), such as influenza. The virus strain that infects horses does not infect people and vice versa!
Every horse person needs to know about zoonotic diseases for their own safety as well as that of their families and employees. These diseases, their clinical signs and common sense advice are discussed in this brochure. Your veterinarian is an important source of information about
zoonotic diseases and is best equipped to advise you on routine equine
vaccinations and preventive medicine.
Roberta M. Dwyer, DVM, MS, DACVPM
Professor, Department of Veterinary Science
UNIVERSITY OF KENTUCKY
College of Agriculture
Salmonellosis
Salmonellosis is a disease caused by the bacteria Salmonella. Most often horses with salmonellosis have acute or chronic diarrhea, but they can also have localized infections in abscesses, joints, eyes and other areas. Wearing disposable gloves and washing hands after handling salmonellosis cases (or any animal with diarrhea) is especially important. Manure from horses with diarrhea should be composted or disposed of where humans and other horses cannot come in contact with it. Symptoms in humans include diarrhea, fever and abdominal cramping.
Ringworm
Dermatophytosis (ringworm) is a common fungal skin infection of many animal species. In horses the problem is primarily caused by Trichophyton equinum. Horses show circular patches of hair loss with crusting and scaling of the skin. People become exposed by direct skin contact with infected horses or potentially through contact with contaminated equipment. The most common symptom is itchiness.
Rabies
Rabies is a viral disease of mammals, including horses. This disease is transmitted to humans via the bite of a rabid animal or contact between the animal's saliva and open wounds or mucous membranes. Only 40-50 horses per year are confirmed as rabies-positive in the United States, but the disease is 100 percent fatal. While infected horses may show behavioral and neurologic changes, rabies is known as "the great imitator" because sometimes animals present with colic or lameness. However, any horse with rabies will usually die within 10 days of the onset of clinical signs. Horses become infected by getting bitten by another rabid animal such as a skunk, raccoon, bat, fox, etc. Rabies vaccination for all horses is recommended by the American Association of Equine Practitioners. In humans, symptoms develop one to three months after being bitten. Because of the seriousness of bacterial infections by animal bites, any human bitten by an animal should wash the wound and seek medical treatment. People who have been exposed to a rabid animal and receive immediate anti-rabies medical treatment have excellent outcomes.
Anthrax
Anthrax is a bacterial disease that has caused sporadic animal disease outbreaks in the United States for many years. The bacterial spore can live in the soil for decades, and animals can become infected through ingestion, inhalation and other routes. Infected horses often become acutely ill and die. People can be exposed to anthrax through contact with an infected animal's hide, tissues or blood. Complete protective equipment - including skin, respiratory and eye protection - should be worn by veterinarians when examining a suspected anthrax case. Symptoms in people can range from blisters on the skin to vomiting blood, bloody diarrhea, stomach ache, flu-like symptoms or chest pain.
Rain Rot
Dermatophilosis (rain rot) is a common bacterial skin disease in horses characterized by matted hair and skin lesions that ooze and form clumps. Although a rare zoonosis in healthy people, this disease can be transmitted to humans through direct contact with lesions. Symptoms are sores, usually on the hands and arms.
Brucellosis
Brucellosis is a bacterial disease that causes abscesses and draining tracts on the withers (fistulous withers) and poll (poll evil) in horses and causes disease in many other animal species. People become infected by coming in contact with infected animals, especially cattle, although with aggressive control measures for brucellosis in the United States very few cases are reported in people. Transmission of brucellosis from horses to humans is rare because the disease is very uncommon in horses. Symptoms include fever, headache, back pain and weakness.
Leptospirosis
Leptospirosis is a bacterial disease that causes abortion, eye problems and kidney disease in horses. Transmission from horses to people is very rare in the United States but can occur through direct or indirect contact with infected urine, as well as ingestion of contaminated water. Symptoms include headache, fever, nausea, muscle aches and jaundice (yellow skin and eyes).
Cryptosporidiosis
Cryptosporidiosis is a protozoal parasitic disease that sometimes causes diarrhea in foals, and can cause significant disease in other species. Cryptosporidium can infect many different animals and people through the fecal-oral route. Symptoms in humans include watery diarrhea, stomach cramps, nausea and a poor appetite.
Vesicular Stomatitis
Vesicular stomatitis is a viral disease that causes blisters and ulceration on the tongue and gums and inflammation of the coronary band in horses. Humans with open wounds can potentially become infected by direct contact with the blisters, which are filled with virus. However, even during outbreaks of the disease, infection of veterinarians and laboratory workers is low. The most prominent symptom in humans is a rash.
What About WNV, EEE and WEE?
West Nile virus (WNV), eastern equine encephalitis (EEE) and
western equine encephalitis (WEE) are all zoonotic diseases
that can affect both humans and horses. Mosquitoes transmit
these viruses from an infected bird to a person or a horse.
Infected humans and horses do not develop high enough viral
levels in the blood to enable transmission of the disease to others.
Therefore, these mosquito-borne diseases are zoonotic
from birds to people and horses, not from horses to people!
Vaccination against EEE, WEE and WNV is very effective in
reducing outbreaks of these diseases in horses.
Preventing Disease
A veterinarian can develop a comprehensiveprogram designed to help protect horses and people from infectious diseases and provide early diagnosis that can save horse owners a significant amount of money in the long run! Caretakers should use disposable gloves to handle and treat any sick horse and thoroughly wash their hands after treatments.
A disease is transmissible if the causative agent (bacteria, virus, fungus, parasite, etc.) can be spread from one animal to another. The most common means of zoonotic disease transmission are:
Direct Transmission
ingestion
inhalation
skin contact
contact with mucous membranes or open wounds
bites
Indirect Transmission
Indirect transmission is accomplished by an insect vector (insect bite) or by contact with inanimate objects (e.g., touching towels or other items with fecal contamination, then eating lunch).
Common Sense Precautions
Consult your veterinarian to develop a comprehensive preventive medicine program, including vaccinations and biosecurity.
Have a veterinarian evaluate sick horses, especially those with behavioral changes, including aggression.
Isolate sick horses and take precautions by wearing protective clothing such as separate coveralls and disposable gloves and booties.
Always avoid hand to mouth or nose contact when handling infectious horses.
Wash hands thoroughly with soap and water after handling ill horses, especially those with diarrhea.
Alcohol-based hand sanitizer gels (62% ethyl alcohol) are very effective in killing many bacteria and viruses when used on hands that are not visibly soiled.
If treating a horse with a potentially zoonotic disease, wear disposable gloves and thoroughly wash hands afterward. Consult a veterinarian for a diagnosis and recommendations.
Always consult your physician if you have suspected exposure to a zoonotic disease or have any questions regarding its symptoms, diagnosis or treatment. Tell your physician about any animals you may have been around.
Become educated on horse diseases, especially those common in your area.
For more information, visit saddleupSAFELY.org.
Immunocompromised Individuals and Family Members
People with challenged immune systems, whether by disease, medication or age, can be more susceptible to infectious disease agents in a horse's environment.
Immunocompromised people include:
Cancer patients
Organ transplant patients
People taking immunosuppressive drugs
Patients with HIV/AIDS or other infectious diseases that suppress the immune system
Patients with chronic illnesses or conditions such as cystic fibrosis, diabetes mellitus, etc., that may render them more susceptible to infectious agents
Children under the age of 5
The elderly
Pregnant women (fetal risk)
These individuals should .speak with their physician about added precautions needed when anticipating direct contact with animals or their environments (i.e., barn, water source, etc.). In general, immunocompromised people should not work around sick animals, especially those with diarrhea. Avoid contact with feces or urine, and thoroughly wash hands after contact with animals and prior to eating, drinking, using tobacco products or applying cosmetics. Because of bacteria present in dusty horse environments, some people may be advised to wear an N95 mask to avoid exposure to bacteria and other disease-causing agents.
If a family member not exposed to horses is immunocompromised, the clothing and footwear of people working with horses should be left in a designated area, such as the entryway to the home. Disease-causing organisms on clothing can be a hazard to immunocompromised family members, therefore this clothing should be laundered separately and not handled by the patient. Horse equipment and other materials should be left outside of the home, and the horse handler should wash his or her hands before coming home.
COULD THIS HAPPEN TO YOU?
"I caught ringworm from my mare. She had developed three circular lesions close to her girth area. I treated her with anti-fungal salve and shampoo. I never dreamed I could catch the stuff! I developed a small circular lesion on the inside of my lower leg that quickly grew to two inches. I caught it by riding her bareback from the field to the barn. The sore itched profusely and looked awful. I went to the doctor and got a prescription, which took care of it."
The skin is the largest organ of the body, and skin diseases can be difficult to diagnose. Veterinarians should be called to diagnose skin problems in horses, just as people visit their doctors for diagnosis and treatment. Because skin diseases can be transmitted between horses (and possibly people), disinfect equipment after lending it out, and wear gloves and protective clothing when working with animals that have skin infections.
To obtain copies of the first two Saddle Up SAFELY booklets, please e-mail saddleup@uky.edu, call 859-323-5508, or send your request by mail to:
Saddle Up SAFELY
UK Healthcare
2333 Alumni Park Plaza, Suite 300
Lexington KY 40517
Ways to get
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Saddle Up SAFELY
The Saddle Up SAFELY program can
arrange for speakers to address your
organization about horseback riding
safety issues. Call 859-323-5508
to schedule one of our speakers
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Read Dr. Fernanda C. Camargo's
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Lexington KY 40517
If you have been injured or have caught a disease from being around horses, tell
us about how it happened and how it might have been prevented by going to
saddleupSAFELY.org and using the advice/tip registry.
Those who provide advice that is used on our website will be eligible to win a
variety of prizes, including $150 giftcertificatesforAriat merchandise, helmets
from Pegusus Helmets and Troxel, four reserved seats to a Keeneland race day,
tickets to the Kentucky Horse Park, and more.