Objective—To measure antibody titers against
Leptospira interrogans in serum and vitreous humor
and determine the prevalence of L interrogans in vitreous
humor of horses with recurrent uveitis.
Animals—242 horses (270 eyes) with recurrent
uveitis undergoing vitrectomy and 39 control horses
(54 eyes) without any history or clinical signs of recurrent
uveitis undergoing euthanasia or enucleation for
Procedure—Serum and vitreous humor were tested
for antibodies against 13 serovars of L interrogans.
Vitreous humor was submitted for leptospiral culture;
isolates were typed to the serogroup level.
Results—Leptospira interrogans was isolated from vitreous
humor from 120/229 (52%) horses (126/252
[50%] eyes) with recurrent uveitis but was not isolated
from vitreous humor from 36 eyes of 21 control horses.
Duration of recurrent uveitis was ≥ 1 year for 45 of the
120 (38%) horses from which the organism was isolated.
Geometric mean antibody titers against L interrogans
in the vitreous humor and serum of horses with
recurrent uveitis were 1:1,332 and 1:186, respectively.
Only 91 of 120 (76%) horses from which the organism
was isolated had a 4-fold or greater difference between
serum and vitreous humor antibody titers.
Conclusions and Clinical Relevance—Results suggest
that persistent ocular infection with L interrogans
is common in horses with recurrent uveitis. A 4-
fold increase in vitreous humor versus serum antibody
titers may not be a sensitive test for the diagnosis
of L interrogans-induced recurrent uveitis. We
hypothesize that the immune component of recurrent
uveitis can be directly induced and maintained by persistent
infection of the eye with L interrogans. (J Am
Vet Med Assoc 2001;219:795–800)