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Home / Equine Research Bank / Equine Vet J / Taylorella equigenitalis in Icelandic intact males compared ...
Equine veterinary journal2024; 57(2); 441-448; doi: 10.1111/evj.14121

Taylorella equigenitalis in Icelandic intact males compared with other horse breeds using natural cover.

Abstract: Contagious equine metritis (CEM) is caused by Taylorella equigenitalis. It is a venereal disease that is detected in some breeds more than others and can cause temporary infertility with substantial costs for regular testing, sanitation and retesting. There was a perceived increase in T. equigenitalis-positive cases in Icelandic intact males where natural cover is common. Objective: We aimed to investigate the prevalence of T. equigenitalis in Icelandic intact males and compare to draught horse and Haflinger intact males. We hypothesised that prevalence of T. equigenitalis is higher in Icelandic compared with draught and Haflinger intact males. Methods: Cross sectional. Methods: Swabs from 76 Icelandic, 35 Haflinger, and 51 draught horse intact males were collected on 38 different farms and analysed by qPCR. Animals were further stratified into active breeding and non-breeding animals and age groups (1.5-7.0 and 8.0-26.0 years). Fisher's exact tests and mixed effect logistic regression with 'farm' as random effect were used to estimate differences in odds for T. equigenitalis-positive test results. Results: The overall prevalence of T. equigenitalis in included intact males was 16.7% (27/162). The odds for T. equigenitalis-positive intact males were significantly higher in Icelandic compared with draught and Haflinger intact males (Odds ratio [OR] = 6.42, 95% confidence interval (CI) = 1.43-28.8, p = 0.02). Odds for T. equigenitalis-positive intact males were significantly lower in active breeding compared with non-breeding animals (OR = 0.09, 95% CI = 0.01-0.54, p = 0.009). Age had no significant influence on test results. Conclusions: Convenience sampling with regional restrictions to Southern Germany and Austria, small sample size. Conclusions: Significantly higher odds for T. equigenitalis-positive intact males were found within Icelandic over draught and Haflinger and within non-breeding animals compared with active breeding animals. Findings suggest that non-breeding animals could be a reservoir for T. equigenitalis. Testing for CEM should therefore be routinely performed in Icelandic horses prior to breeding and investigations into epidemiology and reservoirs on affected farms should be initiated.
© 2024 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2024-06-21 PubMed ID: 39031711PubMed Central: PMC11807930DOI: 10.1111/evj.14121Google Scholar: Lookup
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Summary

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Overview

  • The study investigates the prevalence of Taylorella equigenitalis, the bacterium causing contagious equine metritis (CEM), in Icelandic male horses compared to draught horses and Haflingers, especially in natural breeding settings.
  • It found a higher prevalence of T. equigenitalis in Icelandic horses and suggests non-breeding males may act as reservoirs, highlighting the importance of routine testing before breeding.

Background

  • Contagious Equine Metritis (CEM): A venereal disease in horses caused by the bacterium Taylorella equigenitalis.
  • Impact of CEM: It leads to temporary infertility in infected animals and incurs significant costs due to testing, sanitation, and retesting protocols.
  • Disease Detection: Some horse breeds show higher detection rates of T. equigenitalis than others, raising concerns about breed-specific susceptibility or management factors.
  • Context in Iceland: Natural mating (natural cover) is common in Icelandic horses, and recent observations suggested an increase in positive T. equigenitalis cases in Icelandic intact (uncastrated) males.

Research Objective

  • To determine the prevalence of T. equigenitalis specifically in Icelandic intact male horses.
  • To compare this prevalence to that in draught horse and Haflinger intact males.
  • Hypothesis: Icelandic intact males have a higher prevalence of T. equigenitalis compared to the other two breeds.

Methods

  • Design: Cross-sectional study sampling animals on farms.
  • Sample: Swabs collected from 162 intact males across 38 farms:
    • 76 Icelandic horses
    • 35 Haflingers
    • 51 draught horses
  • Testing: Samples analyzed using quantitative polymerase chain reaction (qPCR) to detect the presence of T. equigenitalis.
  • Stratification: Animals classified by:
    • Breeding status (active breeders vs. non-breeders)
    • Age groups (1.5–7 years and 8–26 years)
  • Statistical Analysis:
    • Fisher’s exact tests to assess differences between groups.
    • Mixed-effects logistic regression modeling with ‘farm’ as a random effect to account for farm-level variability.

Results

  • Overall prevalence: 16.7% (27 positive out of 162 horses).
  • Breed Comparison: Icelandic males were significantly more likely to test positive than draught and Haflinger males.
    • Odds Ratio (OR) = 6.42
    • 95% Confidence Interval (CI) = 1.43–28.8
    • p = 0.02 (statistically significant)
  • Breeding Status: Active breeding males had significantly lower odds of testing positive compared to non-breeding males.
    • OR = 0.09
    • 95% CI = 0.01–0.54
    • p = 0.009 (statistically significant)
  • Age: No significant effect on the likelihood of testing positive was detected.

Interpretation and Implications

  • Icelandic intact males have a notably higher prevalence of T. equigenitalis compared to other breeds studied.
  • Non-breeding males may be a significant reservoir of the bacterium, potentially sustaining infection on farms.
  • Active breeding males showing lower prevalence suggests either treatment, management differences, or sampling bias in animals intended for breeding.
  • This supports the critical need for regular, routine testing of Icelandic horses before breeding to control and prevent the spread of CEM.
  • Farm-specific epidemiologic investigations are necessary to understand the persistence and control of the infection within populations.

Limitations

  • The sampling method was convenience sampling, which may limit generalizability.
  • Geographic sampling was restricted primarily to southern Germany and Austria for the draught and Haflinger horses, possibly affecting breed prevalence comparisons.
  • Relatively small sample sizes, especially in the comparison groups, might reduce the precision of prevalence estimates.

Conclusions

  • The study confirms significantly higher odds of T. equigenitalis infection in Icelandic intact males compared to draught and Haflinger breeds.
  • Non-breeding males emerge as a potential reservoir, indicating that targeting these animals in control programs is important.
  • Preventative measures, including routine and systematic testing before breeding, should be emphasized in Icelandic horse populations.
  • Further epidemiological studies on affected farms are recommended to help identify sources and transmission pathways.

Cite This Article

APA
Grabatin M, Fux R, Zablotski Y, Goehring LS, Witte TS. (2024). Taylorella equigenitalis in Icelandic intact males compared with other horse breeds using natural cover. Equine Vet J, 57(2), 441-448. https://doi.org/10.1111/evj.14121

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 57
Issue: 2
Pages: 441-448

Researcher Affiliations

Grabatin, Markus
  • Equine Clinic, Center for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
Fux, Robert
  • Division of Virology, Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, Munich, Germany.
Zablotski, Yury
  • Equine Clinic, Center for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
Goehring, Lutz S
  • MH Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Witte, Tanja S
  • Equine Clinic, Center for Clinical Veterinary Medicine, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.

MeSH Terms

  • Animals
  • Horses
  • Male
  • Horse Diseases / epidemiology
  • Horse Diseases / microbiology
  • Iceland / epidemiology
  • Taylorella equigenitalis / isolation & purification
  • Cross-Sectional Studies
  • Gram-Negative Bacterial Infections / veterinary
  • Gram-Negative Bacterial Infections / epidemiology
  • Gram-Negative Bacterial Infections / microbiology
  • Prevalence

Grant Funding

  • Deutsche Gesellschaft für Pferdemedizin

Conflict of Interest Statement

The authors declare no conflicts of interest.

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Citations

This article has been cited 1 times.
  1. Wasiński B, Złotnicka J, Kubajka M, Olejarczyk M, Szulowski K. Taylorella equigenitalis infections in Poland - results of current diagnostic investigations.. J Vet Res 2025 Sep;69(3):339-344.
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