Comparison of Nose Wipes, Stall Sponges, and Air Samples with Nasal Secretions for the Molecular Detection of Equine Influenza Virus in Clinically and Subclinically Infected Horses.

This research focuses on comparing the effectiveness of different collection methods, including nose wipes, stall sponges, and air samples for detecting equine influenza virus (EIV) in horses showing clinical and subclinical symptoms of the virus. Results highlight that while all methods hold promise, nasal swabs remain the most accurate means of detection.

Research Methods and Conditions

• The research took place during an outbreak of EIV among 27 horses which included five showing clinical symptoms, six with subclinical symptoms, and 16 uninfected horses.
• Different collection methods (nose wipes, stall sponges, and air samples) were compared against the gold standard method of nasal swabs. These samples were collected when the outbreak started and retested every 2-3 days until all participating horses tested negative for EIV using qPCR.
• The researchers aimed to assess how well each method matched with the results of the gold standard nasal swabs in clinically and subclinically infected horses.

Results

• In clinically infected horses, nose wipes and stall sponges identified EIV in all cases while air samples identified the virus in four of the five horses.
• In terms of agreement with the nasal swabs, nose wipes showed a match rate of 89%, stall sponges were at 78%, and air samples only at 44%.
• Among subclinically infected horses, the effectiveness of nose wipes and stall sponges decreased due to shorter shedding periods of the virus in these cases. Nose wipes and stall sponges detected EIV in five and four out of six horses, respectively, and only one air sample registered positive for EIV.
• When the samples were compared with the gold standard nasal swabs, the overall agreement in subclinically infected cases was 54% for stall sponges, 50% for air samples, and 45% for nose wipes.

Conclusion

• These novel methods of collecting non-invasive samples have potential as alternatives to nasal swabs for detecting EIV in both clinically and subclinically infected horses.
• However, due to lower accuracy, these methods should be used as a second choice, or in instances where nasal swab collection is impractical such as large scale outbreaks or difficult to test horses.
• There was also indication that pooling different samples collected from the same horse can boost the accuracy of EIV detection. This is especially beneficial in the detection of subclinical cases.