Farm size and biosecurity measures associated with Strongylus vulgaris infection in horses

Selective anthelmintic treatment, advocated due to evolving anthelmintic resistance, has been associated with an increase in Strongylus vulgaris prevalence. Reverting to routine interval anthelmintic treatments is not viable and therefore, identifying other management factors correlated with S. vulgaris infection is vital.BACKGROUNDSelective anthelmintic treatment, advocated due to evolving anthelmintic resistance, has been associated with an increase in Strongylus vulgaris prevalence. Reverting to routine interval anthelmintic treatments is not viable and therefore, identifying other management factors correlated with S. vulgaris infection is vital.To investigate possible risk factors associated with the presence of S. vulgaris infection in resident horses on Swedish horse establishments.OBJECTIVESTo investigate possible risk factors associated with the presence of S. vulgaris infection in resident horses on Swedish horse establishments.Internet-based questionnaire survey.STUDY DESIGNInternet-based questionnaire survey.A questionnaire, created using the internet-based survey platform Netigate, was distributed to owners of equine establishments throughout Sweden via established equine platforms and social media channels. The survey was available for response from 21 May until 1 September 2022. Questions were closed ended with branching logic paths.METHODSA questionnaire, created using the internet-based survey platform Netigate, was distributed to owners of equine establishments throughout Sweden via established equine platforms and social media channels. The survey was available for response from 21 May until 1 September 2022. Questions were closed ended with branching logic paths.Four factors were significantly associated with S. vulgaris infection, with an increased odds of infection seen in livery yards (odds ratio [OR] 1.67, 95% confidence interval [CI] 1.18-2.36, p = 0.004) and premises with more than 10 resident horses (OR 2.42, 95% CI 1.64-3.56, p