Horse Leptospirosis and Eye Disease

Leptospirosis infection in horses is strongly linked to equine recurrent uveitis (ERU), the leading cause of blindness in horses worldwide.

Key Facts

Leptospira interrogans serovar Pomona is the most common cause of equine leptospiral uveitis
Equine recurrent uveitis (ERU) is the leading cause of blindness in horses globally
Leptospiral uveitis has a delayed onset - uveitis may develop months to years after infection
Appaloosas are genetically predisposed to ERU and are overrepresented in affected populations
Intravitreal gentamicin injection can terminate the immune-mediated cycle in some horses
Surgical cyclosporine implant placement into the eye provides immunosuppression to prevent flares

Welfare Considerations

ERU causes repeated bouts of painful eye inflammation that progressively damage the eye's internal structures. Each episode of uveitis carries risk of cataracts, glaucoma, retinal detachment, and eventual blindness. The pain during acute uveitis episodes is significant - affected horses squint, tear excessively, and show light sensitivity. Chronic pain between episodes causes behavioral changes and reduced quality of life. Early recognition of uveitis, prompt anti-inflammatory treatment, and specialist referral are critical to slowing progression. The cyclosporine implant has transformed outcomes in Appaloosas and other severely affected horses by significantly reducing flare frequency.

What You Can Do

Recognize uveitis signs: squinting, tearing, cloudy eye, light sensitivity - seek veterinary care same day
Start anti-inflammatory treatment promptly during acute episodes to minimize damage
Refer horses with recurrent uveitis to an equine ophthalmologist for specialist management
Discuss cyclosporine implant placement for Appaloosas and other horses with frequent flares
Vaccinate horses against leptospirosis where vaccination is available and leptospiral uveitis is common
Manage leptospirosis risk by reducing contact with wildlife, controlling rodents, and fencing water sources