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Home / Equine Research Bank / Equine Vet J / Risk factors for insidious uveitis in the Knabstrupper breed...
Equine veterinary journal2022; 55(5); 820-830; doi: 10.1111/evj.13879

Risk factors for insidious uveitis in the Knabstrupper breed.

Abstract: 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. Methods: 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). Conclusions: 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.
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Publication Date: 2022-10-24 PubMed ID: 36199161DOI: 10.1111/evj.13879Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article investigates the risk factors associated with equine recurrent uveitis (ERU), a leading cause of blindness in horses, particularly in the Knabstrupper breed. Through a detailed examination of 116 horses, the study found a correlation between certain genotypes and age, concluding that additional studies were necessary for an improved understanding and management of ERU.

Research Methodology

  • The study was conducted as a cross-sectional type, with ocular examinations performed on 116 Knabstrupper horses.
  • Depending on identified anomalies, horses were classified as suspect, ERU-affected or free of clinical signs.
  • To assess exposure to Leptospira spp, microagglutination testing (MAT) of the serum was conducted.
  • Several risk factors were analyzed, including clinical signs, age, sex, base color, coat pattern, LP and PATN1 genotypes, percent white at birth, progressive roaning, and Leptospira.
  • All these factors were evaluated via multivariable exact logistic regression, taking into account potential clustering at the barn level.
  • An additional pedigree analysis involving 20 cases and 21 controls was carried out, with calculations for coefficients of coancestry (CC) and inbreeding.

Research Findings

  • The study found a 20.7% prevalence of insidious uveitis in the sample of Knabstrupper horses.
  • As with previous research focused on Appaloosas, LP homozygotes had higher odds of uveitis, categorized by an LP/LP OR of 7.64 (with a 95% CI of [0.8 to +INF]) and a statistical significance of p=0.04. This suggests a genetic risk factor to ERU linked to the LP allele.
  • Age was also identified as another significant risk factor. After accounting for LP, the 16-20 age group had higher odds compared with the youngest group with an OR of 13.36 (95% CI [1.4-213.4], p=0.009).
  • The comparison of average CC showed a significant difference between cases and controls, suggesting an element of genetic risk in terms of inherited traits.

Conclusions and Future Work

  • The study acknowledged that the relatively small sample size and insidious nature of uveitis may have limited the detection of younger affected horses and consequently affected the power for detecting other associations.
  • However, it was concluded that genotyping for LP could be an effective strategy for assessing the risk of ERU in Knabstrupper horses.
  • The research encourages further studies to develop robust risk models for early detection and improved clinical management of ERU, especially across LP breeds.

Cite This Article

APA
Kingsley NB, Sandmeyer L, Parker SE, Dwyer A, Heden S, Reilly C, Hallendar-Edman A, Archer S, Bellone RR. (2022). Risk factors for insidious uveitis in the Knabstrupper breed. Equine Vet J, 55(5), 820-830. https://doi.org/10.1111/evj.13879

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 55
Issue: 5
Pages: 820-830

Researcher Affiliations

Kingsley, Nicole B
  • Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California - Davis, Davis, California, USA.
  • Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
Sandmeyer, Lynne
  • Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Parker, Sarah E
  • Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Dwyer, Ann
  • Genesee Valley Equine Clinic, LLC, Scottsville, New York, USA.
Heden, Sanna
  • Distriktsveterinärerna, Falköping, Sweden.
Reilly, Camilla
  • Heste-Dyrlaegen, Taastrup, Denmark.
Hallendar-Edman, Anna
  • Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Archer, Sheila
  • Independent Researcher, Sayward, British Columbia, Canada.
Bellone, Rebecca R
  • Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California - Davis, Davis, California, USA.
  • Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.

MeSH Terms

  • Animals
  • Horses
  • Cross-Sectional Studies
  • Horse Diseases / diagnosis
  • Uveitis / diagnosis
  • Uveitis / veterinary
  • Leptospira
  • Risk Factors

Grant Funding

  • Knabstrupperforeningen for Danmark
  • D16EQ-028 / Morris Animal Foundation
  • 18-17 / UC Davis Center for Equine Health

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Citations

This article has been cited 1 times.
  1. Kirmse L, Thieme K, Doherr MG, Eule JC. Evaluation of Laboratory Techniques for the Diagnosis of Leptospira-Associated Equine Recurrent Uveitis (ERU) With Focus on the Goldmann-Witmer Coefficient. Vet Ophthalmol 2026 Jan;29(1):e70132.
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