Equine Veterinary Journal Early View April 2017
By Heather Ferguson
The role of Leptospira spp. in horses affected with recurrent uveitis in the UK
Malalana, R. J. Blundell, G. L. Pinchbeck and C. M. McGowan
This study aimed to provide information on the role of Leptospira infection in equine recurrent uveitis (ERU) cases in the UK. A total of 30 eyes enucleated from ERU cases and 45 eyes from control cases were examined histologically for uveitis. Blood and aqueous humour from all eyes were also tested for Leptospira antibody levels using a microagglutination test.
All eyes from the ERU group showed evidence of uveitis, such as lymphocytic inflammation of choroid and ciliary body, uveal haemorrhage and retinal detachment. There was no evidence of disease in the control group.
Just over half of horses (65% ERU cases and 41% controls) were serologically positive for Leptospira, the most commonly detected serovars being bratislava, autumnalis, copenhageni and australis. There was no significant difference in serum antibody titres between the groups. Six eyes (8%) had detectable Leptospira antibodies in the aqueous humour, all ERU cases, meaning that a positive antibody titre in aqueous humour was significantly associated with ERU. When these cases were compared with ERU cases without positive antibody titres in aqueous humour, there was no significant difference in serum antibody titres, suggesting serum antibody levels may not be helpful in differentiating Leptospira-associated ERU from other initiating causes.
The prevalence of Leptospira infection in ERU cases in the UK is low. Serum antibody levels do not help differentiate Leptospira-associated cases and testing of aqueous humour is required to confirm involvement of Leptospira in ERU cases.
Photo: Practical Horseman Mag