Identifying the species-origin of faecal droppings used for avian influenza virus surveillance in wild-birds.

Abstract

BACKGROUND: Avian influenza virus (AIV) surveillance in birds is important for public health. Faecal droppings from wild-birds are more readily available for such studies, but the inability to identify the species-origin of faecal samples limits their value. OBJECTIVES: To develop, optimise, and field-test a method to simultaneously detect AIV and identify the species-origin from faecal samples. STUDY DESIGN: Analytical sensitivity of the species-identification RT-PCR was assessed on serial dilutions of faecal droppings. Overall sensitivity of the methods for species-identification and AIV detection was assessed on 92 faecal and cloacal samples collected from wildlife, poultry markets, and experimentally H5N1-infected birds. RESULTS: All 92 samples were correctly identified to 24 different species, with a detection limit of 2.8mug of faecal material. All 20 specimens previously shown by virus culture to be positive for influenza virus were correctly identified by RT-PCR for influenza A using the same nucleic-acid extracts used for species-identification. CONCLUSION: We have optimised and evaluated a method for identifying the species of origin and detecting AIV from bird faecal droppings that can be applied to routine surveillance of influenza viruses in wild-birds.