Evaluation of Leptospira species as a cause of endogenous uveitis in cats: a pilot study

ObjectivesAlthough Leptospira species infections can be associated with intraocular inflammation in dogs and horses, there is limited information regarding the role these agents play in feline uveitis. The primary objective of this study was to report the prevalence of antibodies to Leptospira species and the presence of Leptospira species DNA in samples from cats with endogenous uveitis. The secondary objective was to assess for coinfections with Bartonella species, Toxoplasma gondii and eubacteria.MethodsSerum and aqueous humor (AH) samples from 37 cats diagnosed with endogenous uveitis that had been stored at -80°C were selected for this study based on sample availability. PCR assays for Leptospira species, T gondii, Bartonella species and 16S eubacterial rDNA were performed on AH. Sera were evaluated for antibodies to Leptospira species (microscopic agglutination test [MAT]), Bartonella species (IgG ELISA) and T gondii (IgM and IgG ELISA).ResultsAlthough sera from 2/37 (5.4%) cats were positive for antibodies to Leptospira interrogans serovar Pomona by MAT (1:100 titers), all AH samples were negative for DNA of Leptospira species. One AH sample was positive for DNA of a Streptococcus species but all were negative for DNA of T gondii and Bartonella species. Serum antibodies to Bartonella species (21/37, 56.8%), T gondii (7/37, 18.9%) or multiple agents (5/37, 13.5%) were common.Conclusions and relevanceAlthough the results of this study cannot be used to prove or refute Leptospira species as a cause of endogenous uveitis in cats, the detection of specific antibodies to Leptospira Pomona in the sera of two cats suggests that a larger cohort of cats should be tested to further evaluate the hypothesis. The AH of one cat was positive for the DNA of a Streptococcus species and future studies should investigate if post-streptococcal uveitis syndrome can also be found in cats.