Seroprevalence and factors associated with seropositivity to equine arteritis virus in Spanish Purebred horses in Spain.

This research investigates the prevalence of Equine viral arteritis (EVA)—a disease caused by equine arteritis virus (EAV)—in Spanish Purebred horses in Spain. In particular, it attempts to identify which horse and studfarm factors are correlated with this seropositivity.

Objective and Methodology

• The study’s goal was to determine the seroprevalence (the level of a population that has developed antibodies against an infection) of EAV in Spanish Purebred horses bred in central Spain. It also aimed to identify potential horse related and studfarm related factors that could be associated with EAV seropositivity.
• The researchers conducted a cross-sectional study on serum samples from 555 Spanish Purebred horses, collected over a span of two years (September 2011 – November 2013) from 35 different studfarms.
• The serum samples were tested using a commercially available EAV antibody ELISA (a test that quantifies the antibodies) and seroneutralisation (test to measure the ability of serum to neutralize viruses) was used as the confirmatory test for samples with positive and questionable results.
• The authors also collected data on factors potentially linked to EAV seropositivity using a questionnaire and applied random effects logistic regression for data analysis.

Results and Findings

• The researchers found that EAV seroprevalence in Spanish Purebred horses, after standardizing for sex distribution in the reference horse population, was approximately 16.8%. This rate falls within a confidence interval of 5.2% to 28.5%.
• Factors positively associated with EAV seropositivity were found to be an increased number of breeding mares on the studfarm and an increased rate of mares with reproductive issues over the last 12 months.
• Mares that had been vaccinated against Equine herpesvirus-1 (EHV-1) and -4 (EHV-4) showed a positive correlation with EAV seropositivity.

Conclusion and Implication

• The findings of this study are crucial for introducing appropriate biosecurity measures in studfarms. The presence of EAV and the identified factors associated with its presence can inform preventative measures and efficient detection methods, thereby contributing to the overall health and well-being of the horse population.