INTRAOCULAR AND SERUM ANTIBODY-TITERS TO LEPTOSPIRA SEROVARS IN 150 HORSES SUBJECTED TO VITRECTOMY BECAUSE OF EQUINE RECURRENT UVEITIS (ERU)

Between February 1993 and July 1997, 150 horses suffering from recurre nt uveitis were subjected to pars plana vitrectomy. In these horses, a ntibody titers to Leptospira serovars were determined in serum samples and in samples from diluted vitreous collected during vitrectomy. Alt hough the vitreous samples were diluted with 250 mi of balanced salt s olution, in 86 of the 150 vitreous samples (= 57%) the antibody titers were higher than in the serum samples. Additionally, serum samples fr om 77 horses suffering from ERU, but which were not subjected to vitre ctomy, and serum samples from 97 horses with clinically normal eyes we re analyzed for antibodies to Leptospira serovars. Among the 227 horse s with ERU (150 treated surgically, 77 treated conservatively) 50 hors es (50 of 227 = 22%) had serum antibody titers to Leptospira serovars of greater than or equal to 1 : 800. Among the 97 horses with clinical ly normal eyes, 24 horses (24 of 97 = 25%) had serum antibody titers t o Leptospira serovars of greater than or equal to 1:800. In undiluted vitreous samples from 20 horses with clinically normal eyes, no antibo dy titers to Leptospira serovars could be detected. Among the 150 hors es with ERU, 90 animals (90 of 150 = 60%) had antibody titers of great er than or equal to 1 : 100 in the diluted vitreous samples, the diffe rence being highly significant (p < 0.001). The findings are discussed in relation to the: etiology of recurrent uveitis in horses.