Comparison of flocked and rayon swabs for the molecular detection of selected equine viruses and bacteria from nasal secretions of healthy horses

Acute upper respiratory tract infections of horses are a common medical entity caused by a variety of viral and bacterial pathogens. While such infections are often considered a self-limiting condition affecting predominantly young horses, the financial impact through temporary loss of use, cancellation of horse events, costs and labour associated with biosecurity protocols, and direct treatment costs seem relevant to the equine industry.1 Therefore, timely laboratory diagnostics are needed to determine the aetiological agent(s), institute infection control measures and improve surveillance. Quantitative PCR (qPCR) has become the diagnostic tool of choice based on its high sensitivity and specificity, quick turnaround time, cost-effectiveness and panel testing.2 Given the clinical relevance of respiratory pathogens, it is important to use the best collection system that would provide the highest detection yield in nasal secretions. While standard rayon swabs are routinely used for the collection of nasal secretions in horses, flocked swabs have demonstrated superior performance for the detection of human respiratory, vaginal and gastrointestinal pathogens.3–5 The aim of this study was to determine if there is a difference in the performance of flocked swabs over standard rayon swabs in detecting nasal carriage of ubiquitous viruses and bacteria among healthy adult horses. Thirty-one healthy adult horses presented to the William R Pritchard Veterinary Medical Teaching Hospital, University of California at Davis, for routine dental care were enrolled in this study. Each horse was swabbed once with a flocked swab (Becton, Dickinson and Company, Franklin Lakes, New Jersey, USA) and a standard rayon swab (Puritan Products, Guilford, Maine, USA) using opposite nasal passages in randomised order. All the nasal swab collections were performed by the same experienced veterinarian as follows: each nasal ventral passage was swabbed by circulating each swab five times while rotating the swab and exerting …