Detection of intraocular Leptospira spp. by real-time polymerase chain reaction in horses with recurrent uveitis in Belgium.
Authors: Sauvage A C, Monclin S J, Elansary M, Hansen P, Grauwels M F
Journal: Equine veterinary journal
Summary
# Editorial Summary: Leptospira and Equine Recurrent Uveitis in Belgium Equine recurrent uveitis (ERU) represents a significant welfare concern for horse owners, yet its aetiological complexity means cases often go undiagnosed. Sauvage and colleagues investigated the prevalence of intraocular Leptospira spp. in 66 eyes from 59 horses with ERU and 50 control eyes from healthy horses using real-time PCR targeting the lipL32 gene, sampled between 2015 and 2017 at the University of Liège. Leptospira DNA was detected in 30.3% of ERU-affected eyes (20/66), with positives identified in aqueous humour (n=11), vitreous humour (n=17), or both (n=8), whilst all control eyes tested negative, establishing leptospirosis as a meaningful differential diagnosis in the Belgian equine population. Notably, the correlation between results from aqueous and vitreous humour samples was low (phi=0.47), indicating that sampling both media substantially increases diagnostic sensitivity and should be standard practice when ERU is suspected. For practitioners managing recurrent uveitis cases—particularly where clinical response to conventional therapy is suboptimal—Leptospira serology coupled with intraocular PCR warrants serious consideration, though limitations include inability to determine serovars with this methodology and the need for further work establishing whether detection represents active infection or chronic sequelae.
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Practical Takeaways
- •Consider Leptospira infection as a potential cause when investigating recurrent uveitis cases in Belgium; approximately 1 in 3 ERU cases may be leptospirosis-related
- •When sampling for diagnostic purposes, obtain both aqueous and vitreous humour samples when possible, as Leptospira detection in one medium does not reliably predict presence in the other
- •Real-time PCR testing of intraocular fluids can support diagnosis, but serovars cannot be identified with the lipL32 qPCR method used in this study
Key Findings
- •Leptospira spp. DNA detected in 30.3% (20/66) of eyes with equine recurrent uveitis in Belgium
- •Vitreous humour was positive in 17 samples and aqueous humour in 11 samples, with 8 horses positive in both media
- •All 50 control eyes from healthy horses were negative for Leptospira spp.
- •Phi-correlation of 0.47 between aqueous and vitreous humour PCR results indicates low association between the two media