Performance of a microfluidic immunofluorescence assay kit for equine influenza virus antigen detection.
Authors: Kawanishi Nanako, Kinoshita Yuta, Kambayashi Yoshinori, Bannai Hiroshi, Tsujimura Koji, Yamanaka Takashi, Cullinane Ann, Nemoto Manabu
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Microfluidic Immunofluorescence for Equine Influenza Detection Rapid on-site diagnosis of equine influenza virus (EIV) is critical for controlling respiratory disease outbreaks and implementing timely movement restrictions, yet current point-of-care tests remain suboptimal. Researchers evaluated a microfluidic immunofluorescence assay kit (previously validated for human influenza and SARS-CoV-2) against nasopharyngeal swabs from experimentally infected horses, benchmarking sensitivity and specificity against real-time RT-PCR and two commercially available rapid antigen kits. The microfluidic assay detected all 11 EIV strains tested and demonstrated 60.7% sensitivity on clinical samples—matching silver amplification immunochromatography kits but outperforming standard immunochromatography (53.6%)—whilst showing high specificity with no cross-reactivity to nine non-EIV pathogens including equine coronavirus. Although the 60.7% sensitivity means this kit would miss approximately 4 in 10 infected horses, its 12-minute turnaround time and improved performance over some existing rapid tests could make it a practical field tool for outbreak response, particularly when combined with clinical assessment and follow-up laboratory confirmation for negative results.
Read the full abstract on PubMed
Practical Takeaways
- •This rapid 12-minute test provides a practical point-of-care diagnostic option for EIV detection in field settings, supporting timely movement restrictions and outbreak control
- •Sensitivity of approximately 61% means negative results should not definitively rule out EIV infection—consider confirmatory RT-PCR testing if clinical suspicion remains high
- •The assay's high specificity for EIV antigens and lack of cross-reactivity with other equine pathogens makes it suitable for distinguishing EIV from similar respiratory diseases in horses
Key Findings
- •Microfluidic immunofluorescence assay kit successfully detected 11 EIV strains with a 12-minute turnaround time
- •Sensitivity was 60.7% on nasopharyngeal swab samples from experimentally infected horses, matching silver amplification immunochromatography but exceeding standard immunochromatography (53.6%)
- •High specificity demonstrated with no cross-reactivity to nine non-EIV viruses including equine coronavirus and seven bacteria
- •Microfluidic assay shows potential as an effective field diagnostic tool for rapid EIV detection comparable to existing rapid antigen detection kits