Detection of Leptospira interrogans DNA and antigen in fixed equine eyes affected with end-stage equine recurrent uveitis.

This research aims to investigate the presence of Leptospira DNA and antigens in the eye tissue of horses suffering from end-stage equine recurrent uveitis (ERU), a major cause of horse blindness.

Research Methodology and Participants

• The study included 30 horses in total: the control group consisted of 10 horses with normal eyes and 10 horses with a non-recurrent form of uveitis.
• The experimental group included 10 horses diagnosed with ERU based on their clinical signs and histological lesions.
• Eye tissue sections from all these horses were obtained for the study.

Research Techniques used

• The research employed immunohistochemical staining methods, where sections of the horses’ eyes were stained with a set of rabbit anti-Leptospira polyclonal antibodies.
• DNA extractions were performed using a commercial kit intended for fixed tissue.
• Real-Time PCR analysis, a technique used to monitor the amplification of a targeted DNA molecule during the PCR, was used on the extracted DNA.
• The sequence for this PCR was designed from alignments of available Leptospira 16S rDNA partial sequences obtained from GenBank, an open-access database for genome sequences.

Results of the Study

• The study found Leptospira antigen in 2 out of 10 samples from the ERU horses via the immunohistochemical assay, and no antigen was detected in the control group.
• However, none of the test or control samples showed the presence of Leptospira DNA through Real-Time PCR analysis.

Conclusion of the Research

• The research concludes that Leptospira, though implicated in ERU, is not frequently detectable in fixed ocular tissues of horses affected with the condition when using traditional methods like immunohistochemical staining and Real-Time PCR analysis.
• The lower frequency of Leptospira detection in this study also points out that the previously reported rates for fresh ERU-affected aqueous humor and vitreous samples could be higher.