Evaluation of “SNAP® Lepto”-ELISA and comparison with MAT and PCR results for diagnosis of leptospiral uveitis in horses using intraocular samples

Abstract

Chronic intraocular leptospiral infection is the most common cause for recurrent uveitis in equids. History and a combination of typical ophthalmological findings can lead to suspected diagnosis of leptospiral induced uveitis. Testing intraocular fluids had been shown to be the most valuable tool for providing evidence of an intraocular leptospiral infection. The most appropriate treatment for recurrences of leptospiral uveitis is vitrectomy, whereas vitrectomy in non-leptospiral uveitis cases is less successful in regard of avoiding further damage to effected eyes. However, in cases in which clinical and ophthalmological findings are not typical for leptospiral induced uveitis, preoperative testing of aqueous fluid can be indicated to evaluate an indication for vitrectomy. Until now, for save sampling of aqueous humour, a general anaesthesia was necessary for paracentesis of the anterior chamber, and a second was necessary for vitrectomy in case of leptospira-positive laboratory results (either antibodies using microscopic agglutination tests (MAT), enzyme-linked immunosorbent assays (ELISA) or polymerase chain reactions (PCR) detecting LipL32). A quick ELISA test, the SNAP ® Lepto, has recently been made available to detect antibodies directed against LipL32 of pathogenic leptospires in any species. In order to evaluate the SNAP ® Lepto and to test whether it is effective with intraocular samples (aqueous and vitreous humour) from horses, 118 samples from equine eyes suffering from recurrent uveitis and 120 samples from equine control eyes were taken and tested with SNAP ® Lepto (detecting antibodies directed against LipL32), MAT (detecting antibodies directed against ten different serovars) and PCR (detecting the LipL32 antigen). If one of these tests was positive, an intraocular leptospiral infection was assumed.The result was that SNAP ® Lepto was positive in 114 out of 118 intraocular samples (97 %) from horses suffering from recurrent uveitis. SNAP ® Lepto was even superior to MAT, with a sensitivity of 0.97 (MAT 0.93). PCR was positive with fluids from eyes suffering from uveitis in 70 % of samples. There were no positive PCR results in any SNAP ® Lepto-negative samples from uveitic eyes and the MAT was positive in four SNAP ® Lepto-negative samples. On the other hand, SNAP ® Lepto gave a positive result in eight MAT-negative samples from eyes with uveitis. Furthermore, none of the antibody tests was positive regarding any sample from the control eyes, and PCR was positive in one single sample from a control eye. It can be concluded that SNAP ® Lepto, which gives a result within 10 minutes, is a valuable test method for detecting antibodies directed against LipL32 in intraocular fluids from horses. In the case of a negative result, MAT and PCR can be performed subsequently to reduce false negative results. Keywords: chronic intraocular leptospiral infection, equine recurrent uveitis (ERU), MAT, ELISA, serum, SNAP ® Lepto, anterior chamber fluid, vitreous Citation: Wollanke B., Geiger T., Gerhards H. (2018...

In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis

“…For example, anti-Leptospira antibodies are regularly detected in vitreous material obtained during vitrectomies [13,15,21,[32][33][34][35][36][37][38][39][40][41]. These antibodies are detected using the micro agglutination test (MAT), and various enzyme-linked immunosorbent assays (ELISA) [42,43]. In other studies, Leptospira spp.…”

“…are cultured and anti-Leptospira antibodies are detected in the same vitreous samples [13,21,32,35,39,[44][45][46]. In addition, lipL32 gene or 16S-rRNA are detected by a polymerase chain reaction (PCR) in up to 70% of intraocular samples collected from affected horses [32,39,[43][44][45].…”

“…In addition to direct evidence of the leptospiral infection of vitreous samples from eyes affected with ERU, evidence of autoimmunity also exists [49]. However, Prof. Deeg's research group [50] performed all investigations using vitreous samples, from which leptospiral infections were also regularly detected [13,21,39,[41][42][43]46]. Furthermore, while vitrectomy removes the vitreous material, potential autoantigens from other tissues -especially the lens and retina-remain in the eye [18,39] which contradicts the idea of autoimmunity [39,51].…”

Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp.

“…For this reason, aqueous humor testing is indicated preoperatively in questionable ERU cases [5,6,11,[65][66][67][68][69]. If either anti-Leptospira antibodies are detectable in the aqueous humor and/or the LipL32 gene of pathogenic Leptospira spp.…”

Serological Survey of Leptospira Infection in Arabian Horses in Poland

“…The testing of intraocular fluids is the most valuable tool for confirming leptospiral origin of uveitis and also for choosing the proper therapeutic protocol. Detection of pathogenic bacteria or anti-Leptospira antibodies in the eye indicates that trans-pars-plana vitrectomy is a treatment of choice for recurrences, whereas in other cases, vitrectomy is less effective in reducing the recurrence rates and protecting the affected eye from further damage [2][3][4][5][6][7][8][9][10].…”