What is Leptospirosis? 

Leptospirosis is caused by the gram-negative spirochete bacteria Leptospira spp. The organism colonizes the mucous membranes of a susceptible horses. Subsequently circulating in the blood (bacteremia) the organism can invade organs such as kidneys, placenta, fetus, and eye. The bacteremia can last for several days and can cause persistent fever, but rarely are clinical signs noted unless renal failure or abortion occurs.

Clinical Signs: The following are potential clinical signs: 

• Fever
• Loss of appetite 
• Signs of moon blindness (inflammation within the eye causes tearing, swelling, discharge and cloudiness
• Abortion
• Kidney and liver failure can occur with severe infections 
• Death 

Diagnosis: Leptospira abortion is diagnosed  by means of fluorescent antibody testing (FAT) or immunohistochemical evaluation of tissue samples of the placenta, umbilical cord, fetal liver, or fetal kidney. PCR testing is preferred for evaluation of fluids, such as urine, ocular fluids, and blood samples.

Treatment: In acute leptospirosis, systemic antimicrobials such as enrofloxacin, penicillin, tetracyclines, or aminoglycosides are useful, but this is not the case with recurrent uveitis. Intravitreal injections of low-dose, preservative-free gentamicin has been reported to be effective in preventing further episodes of uveitis

Prevention: A Leptospira Pomona bacterin is approved for use in horses to prevent L Pomona bacteremia. By preventing bacteremia, it may prevent Leptospira-associated abortions, renal failure, and uveitis