Avian Influenza Virus Antigen Test Card (Colloidal Gold Method)

Target and Hazard: Avian influenza virus (AIV) is a type A influenza virus of the family Orthomyxoviridae that infects chickens, ducks, geese and many wild birds. The avian influenza caused by its highly pathogenic strains is a Class I animal disease in China, and some subtypes can also cross the species barrier to infect humans. The virus is shed in respiratory secretions and faeces and spreads rapidly between flocks by direct contact and via contaminated feed, water, equipment, personnel and vehicles, frequently moving along live-bird trade and transport routes; infected flocks show a sharp drop in egg production and rising mortality, and every minute saved in detection reduces the risk of spread.

Significance of Testing: This card targets the type-specific antigen shared by all type A avian influenza viruses and works as a broad-spectrum screening antigen test: it does not differentiate subtypes, but gives a positive signal whenever type A avian influenza virus is present, which is useful when the subtype is still unknown and the immediate question is simply whether avian influenza is involved. It suits on-site investigation of suspected outbreaks, immediate testing of dead birds, routine surveillance of poultry houses and live-bird markets, and pre-movement spot checks. Combined with the H5, H7 and H9 subtype antigen cards it forms an on-site testing set that first establishes whether the virus is present and then which subtype it is. A positive antigen result indicates current infection and must be reported and laboratory-confirmed per national regulations.

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

Performance and Applications: No equipment required; visual reading in 10–15 minutes; samples: tracheal/cloacal swab eluate, tissue homogenate; store and ship at 2–30 °C, shelf life 18 months. Suitable for rapid on-site testing on poultry farms, at poultry cooperatives, live-bird markets, slaughterhouses, primary veterinary stations and border quarantine. Method: colloidal gold immunochromatographic assay (double-antibody sandwich) | Samples: tracheal/cloacal swabs, tissue homogenate | Time to result: 10–15 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-PCR/virus isolation are subject to our internal QC report.