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Research article - Peer-reviewed, 2022

Risk factors for insidious uveitis in the Knabstrupper breed

Kingsley, Nicole B.; Sandmeyer, Lynne; Parker, Sarah E.; Dwyer, Ann; Heden, Sanna; Reilly, Camilla; Hallendar-Edman, Anna; Archer, Sheila; Bellone, Rebecca R.


Background Equine recurrent uveitis (ERU) is the leading cause of blindness for horses; previous research implicated the leopard complex spotting allele (LP) as a genetic risk factor for insidious uveitis in the Appaloosa. There is limited information about risk in the Knabstrupper. Objective To evaluate clinical manifestations, disease frequency and potential risk factors for ERU in Knabstrupper horses. Study design Cross-sectional study. Methods Ocular examinations were performed on 116 horses, and based on identified anomalies, horses were classified as suspect, ERU-affected or having no clinical signs. Microagglutination testing (MAT) of serum assessed exposure to Leptospira spp. Clinical signs, age, sex, base colour, coat pattern, LP and PATN1 genotypes, percent white at birth, progressive roaning and Leptospira were assessed as risk factors using multivariable exact logistic regression, accounting for clustering at the barn level. Additionally, a pedigree analysis was performed (n = 20 cases and 21 controls), and coefficients of coancestry (CC) and inbreeding were calculated. Results Prevalence of insidious uveitis in this sample of Knabstruppers was 20.7%. Similar to findings for Appaloosas, LP homozygotes had higher odds of uveitis compared with true solid (N/N) horses (LP/LP OR = 7.64, 95% CI [0.8 to +INF], p = 0.04) and age was also identified as a risk factor. After accounting for LP, the 16-20 age group had higher odds compared with the youngest group (OR = 13.36, 95% CI [1.4-213.4], p = 0.009). The distributions of average CC were significantly different between cases and controls (p = 0.01). Main limitations A relatively small sample size decreased the power for detecting additional associations. The progressive nature of insidious uveitis may have prevented identification of younger affected horses. Conclusions Our data support genotyping for LP to assess risk of ERU in Knabstruppers. Additional studies are necessary to develop more robust risk models across LP breeds for earlier detection and improved clinical management.


ERU; horse; inflammation; insidious uveitis; leopard complex; ocular

Published in

Equine Veterinary Journal
Publisher: WILEY

Authors' information

Kingsley, Nicole B.
University of California Davis
Sandmeyer, Lynne
University of Saskatchewan
Parker, Sarah E.
University of Saskatchewan
Dwyer, Ann
Genesee Valley Equine Clinic
Heden, Sanna
Distriktsveterinärerna Falköping
Reilly, Camilla
Swedish University of Agricultural Sciences, Department of Clinical Sciences
Archer, Sheila
No organisation
Bellone, Rebecca R.
University of California Davis

UKÄ Subject classification

Clinical Science

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