Leptospira Not an Important Factor in Recurrent Uveitis, Researchers Say

As a result of aggressive research efforts, the underlying causes and factors contributing to recurrent uveitis--a painful and debilitating condition that is the leading cause of blindness in horses--are becoming known.

"Recurrent uveitis is an immune-mediated disease, but the inciting cause of the flare-ups remains unknown," explained Brian Gilger, DVM, MS, Dipl. ACVO, a professor in the department of clinical sciences at North Carolina State University's College of Veterinary Medicine. "Various theories exist and there is some evidence to suggest that Leptospira organisms initiate uveitis."

To evaluate the role of intraocular bacteria such as Leptospira in horses with recurrent uveitis residing in the southeastern United States, Gilger and colleagues collected ocular samples from horses diagnosed with recurrent uveitis, normal horses, and horses with ocular inflammation not associated with recurrent uveitis.

"Genetic material (DNA) originating from a bacterial source was not identified in any horses with recurrent uveitis or in the normal horses. Further, there was no significant difference in antibody levels against Leptospira organisms between the three groups," relayed Gilger.

While antibodies against Leptospira were identified in 2/24 (8.3%) of horses with recurrent uveitis, Gilger and colleagues suggest that the continued presence of Leptospira organisms was not directly involved in perpetuating this disease.

"Together, the available data on recurrent uveitis supports the theory that recurrent bouts of uveitis are a result of immune-mediated responses," summarized Gilger.

The study, "Role of bacteria in the pathogenesis of recurrent uveitis in horses from the southeastern United States," was published in volume 69 of the American Journal of Veterinary Research, 2008.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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