To manage and treat a horse with leptospirosis can be frustrating, but basic principles prevail. These horses usually need supportive medicine for addressing kidney failure, anti-inflammatory medications to limit ocular and systemic problems, and antimicrobial therapy in an attempt to help the body rid itself of the bacterial organism.
Treatment strategies for leptospirosis depend on the organ systems affected by infection, and the severity and duration of clinical signs. Usually, antimicrobial therapy with penicillin or derivatives (ampicillin, ticarcillin-clavulanic acid, amoxicillin), cephalosporins, erythromycin, enrofloxacin, ciprofloxacin, tetracycline or doxycycline achieves the best results. Success using antibiotics is somewhat influenced by the duration of clinical signs, i.e., whether the horse is experiencing acute versus chronic disease.
Intravenous fluid therapy support is important particularly for horses in acute kidney failure. Giving the diuretic furosemide further helps to dislodge leptospira organisms from the kidneys.
In addition to antimicrobial therapy, equine recurrent uveitis (ERU) is addressed with anti-inflammatory medications (systemic NSAIDs or topical corticosteroids, for example). Also, products such as topical atropine dilate the pupil to relieve painful spasms within the iris tissues of the eye as well as helping to minimize photosensitivity (sensitivity to light) and tearing. To ameliorate immune responses in the eye, cyclosporine has been helpful in some cases.
The normally occurring blood-ocular barrier makes it difficult to achieve sufficient concentrations of antibiotics in the eye without resorting to local treatment. For severe, non-responsive cases, removing infected vitreous humor in the back of the eye and lavaging the vitreous with gentamycin antibiotic in saline has been shown to relieve ERU symptoms. In one study, 38 horses undergoing this procedure had no recurrence of ERU within six months of vitreous treatment.
The soundest approach to treatment is prevention, as this is a very difficult disease to manage once a horse is infected. If horses live in an area with known prevalence of leptospira organisms and high risk of infection, then all efforts should be taken to protect horses against exposure.