Avian Influenza Virus H9 Subtype Antigen Test Card (Colloidal Gold Method)

Target and Hazard: Avian influenza virus (AIV, genus Influenzavirus A, family Orthomyxoviridae); the H9 subtype is one of the most widely circulating low pathogenic avian influenza (LPAI) subtypes, infecting chickens, ducks and geese via the respiratory and digestive routes and by direct contact, as well as indirectly through contaminated equipment, personnel and vehicles. Affected flocks typically show a sharp drop in egg production, respiratory signs, reduced feed intake and stunted growth; mortality from H9 alone is usually low, but secondary Escherichia coli or Mycoplasma infection can cause significant losses. Because it spreads rapidly and frequently co-infects with other respiratory pathogens, H9 is an economically important disease of layer and broiler production and, as low pathogenic avian influenza, is a Class III animal disease in China while still requiring continued attention for avian influenza control and public health.

Significance of Testing: The card detects H9 subtype AIV antigen directly, enabling rapid on-site screening of suspected cases, quarantine testing of live poultry movements and environmental screening of poultry houses, and identifying infected flocks at an early stage during peak virus shedding. A positive antigen result indicates current virus infection and provides direct evidence for isolation, disinfection, culling and official reporting. Combined with universal and H5/H7 subtype cards, it assists subtype differentiation and outbreak response decisions.

Principle: Colloidal gold immunochromatographic assay (double-antibody sandwich): H9 subtype AIV antigen in the sample binds to gold-labelled anti-H9 monoclonal antibody, migrates along the nitrocellulose membrane and is captured by the H9-specific antibody coated on the test line (T), producing a visible line; the control line (C) confirms test and procedure validity.

Performance and Applications: Simple operation with no equipment; visual reading at 5 minutes; samples: tracheal/cloacal swab eluate, trachea or lung homogenate; storage and shipment at 2–30 °C with an 18-month shelf life. Suitable for on-farm screening at chicken and duck farms, primary veterinary stations, live-bird markets and border inspection; positive results must be reported and confirmed by laboratory testing as required by national regulations. Method: colloidal gold immunochromatographic assay (double-antibody sandwich) | Samples: tracheal/cloacal swab eluate, trachea or lung homogenate | Time to result: 5 min | Reading: visual assessment of T/C lines — a coloured T line indicates a positive result, C line is the procedural control | Format: tests/box (as stated on the label) | Storage: 2–30 °C, cool and dry; shelf life 18 months | Note: sensitivity, specificity, limit of detection, intra-/inter-assay CV and agreement with RT-qPCR/virus isolation are subject to our internal QC report.