Role of Intraocular Leptospira Infections in the Pathogenesis of Equine Recurrent Uveitis in the Southern United States
Master of Science (MS)
Biomedical and Veterinary Medical Sciences - Veterinary Clinical Sciences
To investigate the role of intraocular leptospiral infections in horses with Equine Recurrent Uveitis (ERU), ocular fluid samples were collected from donated and client-owned horses with a history and ocular findings consistent with chronic ERU. Additionally, eyes were harvested from horses with normal ophthalmic examinations as a control group. Blood samples were obtained for Leptospira serology using microscopic agglutination test (MAT). Aqueous and vitreous humor samples were aseptically obtained and submitted for aerobic culture and Leptospira culture, PCR and MAT. Twenty-one control horses (40 eyes) and 31 ERU horses (46 eyes) were available for study. Serology results were available for 48/52 horses: 16/21 control and 23/27 affected horses were positive for at least one serovar; Bratislava was the most common serovar for both groups. Bacillus sp. and Micrococcus sp. were cultured from one control eye; Streptococcus sp. (n=1) and Leptospira (n=6) from eyes with ERU. Leptospira isolated belonged to serogroup pomona (n=4) and grippotyphosa (n=2). PCR results were positive in 14/31 (45%) horses diagnosed with ERU; no control horses were positive by PCR (p=0.0001). MAT was positive for 17/24 of ERU horses (71%) and 1/21 (4.7%) of normal horses (p<0.0001). Horses with ERU had a high prevalence of Leptospira infection based on PCR and MAT results from intraocular fluids compared to controls. Leptospira infection should be considered as a cause of ERU in the southern United States. The diagnosis of these intraocular infections was not aided by serology and required specific, invasive sampling of ocular fluid.
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Polle, Florence, "Role of Intraocular Leptospira Infections in the Pathogenesis of Equine Recurrent Uveitis in the Southern United States" (2012). LSU Master's Theses. 3492.
Carter, Renee T.