Leptospirosis in Horses

Other animals that can also be infected by the Leptospira organism are livestock, dogs, cats, and wildlife. Leptospirosis has been diagnosed worldwide; most cases occur after heavy rains. Once the organism has enter the body it multiplies, spreads to the bloodstream, and is then able to attack the body’s organs. If left untreated, Leptospirosis can cause: 

• Blindness
• Liver damage
• Renal failure
• Harm to the red blood cells
• Mid or late term abortion in pregnant mares

If your horse is experiencing symptoms of  Leptospirosis, it is imperative that he is seen by a veterinarian. Patients that are diagnosed and treated in the early stages of the disease have a much better prognosis.

Leptospirosis is a bacterial infection in horses caused by the Leptospira organism. Leptospirosis is a zoonotic disease, which means it can be transmitted between animals and humans. 

Symptoms of Leptospirosis may include:

• Fever
• Lack of appetite
• Weight loss
• Depression
• Eye redness
• Sensitivity to light
• Eye discharge
• Swelling around the eyes
• Cloudiness in the eyes
• Muscle spasm in the eyes
• Squinting or excessive blinking
• Jaundice
• Abortion
• Uveitis
• Blindness
• Dysuria (difficulty urinating)
• Abdominal pain

Leptospirosis is caused by the Leptospira organism; immune compromised horses are more susceptible to it. The Leptospira organism may be transmitted by:

• An infected animal urinates in the water trough; the horse then drinks the contaminated water
• Ingestion of contaminated stagnant water such ponds
• An infected animal urinates in the hay or grain; the horse then eats the contaminated food
• Infected blood or urine gains access through a cut or abrasion on the horse’s skin
• Infected blood or urine gets in the horse’s eyes, mouth or nostrils

Clinical signs most often seen with this infection are fever, anorexia, and jaundice. Additionally, uveitis is almost always present and may be recurring which is an indication that an illness such as leptospirosis is possible. The veterinarian may note signs of eye discomfort such as redness, tearing, and discharge.

Blood tests and a urinalysis can reveal this illness. Presently, studies are in process, researching the link between fetal death and abortion in horses and the association with leptospirosis. It is believed that bacteria migrates to the placenta or the uterus, causing the demise of the fetus. Post mortem testing is often recommended to determine the cause. Researchers feel that in many cases, the condition of leptospirosis is not diagnosed as the reason for the loss of the animal.

If your horse is diagnosed with Leptospirosis, it is important for the person caring for him to wear gloves and a face shield.  Gloves should also be worn while cleaning the stalls, feeding buckets, and water troughs.

Patients with uveitis may be prescribed non-steroidal anti-inflammatory drugs and topical steroid ointment. Topical ointments may dilate the horse’s pupils and make his eyes sensitive to brightness; therefore, he should be kept in dim lighting. 

Antibiotic therapy may include penicillin, tetracycline, streptomycin or erythromycin. If the horse is dehydrated or anemic, fluid therapy and blood transfusion may be necessary.

In some patients with severe uveitis, the veterinarian may recommend the surgical procedure vitrectomy.  This surgery is meant to help with the painful inflammation of uveitis; it removes the vitreous and any floaters from the eye. Vitrectomy may also help improve your horse’s vision.

It is important to follow the treatment plan the veterinarian has prepared for your horse.  The patient will need to have follow-up visits to monitor his progress and to recheck for the bacteria. 

If your horse underwent surgery the equine ophthalmologist surgeon will provide you with post-operative instructions and a drug therapy treatment plan.  The patient will need to have additional visits to re-examine the eyes.

Prognosis for Leptospirosis depends on how severe the bacterial infection is.  Uveitis may need ongoing medication therapy.  

If other animals shared the pasture with an infected horse, they should be examined and tested for Leptospirosis.  Stalls, buckets and troughs should be cleaned and disinfected.  Free standing water should be eliminated. Rodents can transmit Leptospirosis; therefore, the stalls should be checked for rodent infestations.  

There has recently been a vaccine developed against Leptospirosis called Lepto EQ Innovator.  If you have any questions regarding the vaccine, contact your equine veterinarian.