Inability of real-time reverse transcriptase PCR assay to detect subtype H7 avian influenza viruses isolated from wild birds.

We report a failure of the real-time reverse transcriptase PCR H7 subtyping protocol currently used in national avian influenza surveillance programs. Significant substitutions in primer and probe target sequences were identified, especially in wild bird viruses. The protocol, originally designed for detecting H7 influenza viruses in poultry, is not reliable for wild bird surveillance.