Role of bacteria in the pathogenesis of recurrent uveitis in horses from the southeastern United States.

The research article investigates if bacteria, specifically Leptospira spp., contribute to the pathogenesis of recurrent eye inflammation (equine recurrent uveitis or ERU) in horses from the southeastern United States. However, the results showed no significant role of intraocular bacteria or Leptospira spp. antibodies in the chronic occurrence of this disease, though Leptospira may have contributed to initial cases in some instances.

Research Objectives and Methods

• The research intended to understand the role of bacteria (particularly, Leptospira spp.) in causing ERU in horses from the southeastern United States.
• The tested samples included aqueous humor, vitreous humor, and serum from 24 healthy horses, 52 horses affected with ERU, and 17 horses exhibiting non-ERU-related inflammation.
• To detect bacterial DNA in the samples, a Ribosomal RNA quantitative PCR (real-time PCR) assay was used.
• Furthermore, anti-Leptospira antibody titers were evaluated from aqueous humor and serum samples.

Research Results

• No bacterial DNA was found in either aqueous humor or vitreous humor of either healthy horses or horses with chronic (> 3-month) ERU.
• There was no significant variation in anti-Leptospira antibody titers in the serum or aqueous humor among the three groups of horses.
• Only two horses – one with ERU and one with non-ERU inflammation – showed definitive intraocular production of anti-Leptospira antibodies. This indicates a limited role of Leptospira spp. in these cases.

Conclusions

• The research concluded that, for horses in the southeastern United States, Leptospira organisms might have had a minor role in triggering ERU in some instances, but their continued presence did not directly contribute to the recurrent nature of the disease.
• That means, while bacteria may be implicated in initial instances of ERU, they do not seem to be responsible for the ongoing, recurring nature of ERU, at least not within the population and region studied.