[Intraocular and serum antibody titers to Leptospira in 150 horses with equine recurrent uveitis (ERU) subjected to vitrectomy].

The research article explores the profile of antibodies against Leptospira (a bacterial species) in the blood and eye fluid of horses affected with equine recurrent uveitis (ERU), a chronic eye inflammation condition. The study found that horses with ERU have a notably higher frequency of these antibodies in their eye fluid, suggesting a potential link between leptospirosis infection and the onset of ERU.

Research Background and Methodology

• The researchers studied 150 horses diagnosed with equine recurrent uveitis (ERU), a chronic inflammation of the eye. This is a condition that frequently recurs and can lead to blindness in horses.
• From February 1993 to July 1997, these horses underwent a surgical procedure known as parsplana vitrectomy, which removes vitreous, a jelly-like substance filling the eye.
• During the procedure, samples of the dilute vitreous, as well as serum samples, were collected from the horses.

Findings and Analysis

• The researchers discovered that in 57% of the vitreous samples taken from the horses, antibody titers (a measurement of the concentration of antibodies in the blood) against Leptospira were higher than those found in the serum samples.
• The study also assessed serum samples from 77 other horses with ERU but not treated with vitrectomy, and 97 horses with clinically normal eyes.
• They found that 22% of the 227 horses with ERU (including those that underwent surgery and those that didn’t) had serum antibody titers to Leptospira of ≥ 1:800.
• Among the 97 horses with clinically normal eyes, about 25% also showed titers of ≥ 1:800. However, undiluted vitreous samples from these clinically normal horses showed no traceable titers.
• Lastly, among the 150 horses that had vitrectomy due to ERU, 60% displayed titers of ≥ 1:100 in the diluted vitreous samples, a significant difference compared to the serum antibody concentrations.

Conclusion and Implications

• The significant presence of antibodies against Leptospira in vitreous samples, but not serum, of horses with ERU suggests a strong link between Leptospira infection and the development of ERU.
• The findings lead researchers to discuss the role of Leptospira in the etiology, or cause, of recurrent uveitis in horses, paving the way for further study of this correlation.