Seminar: Andrew Lang

Pathogens on the fly: Dissemination of viral zoonoses and antimicrobial-resistant bacteria by wild birds

This presentation will focus on wild birds and their role in the circulation and dissemination of highly pathogenic avian influenza viruses and antimicrobial-resistant Escherichia coli. Starting in late 2021, there have been repeated introductions of highly pathogenic avian influenza H5 viruses into North America from Eurasia across both the Pacific and Atlantic routes. One introduction was of an H5N5 strain that was first detected in Newfoundland in 2023 and subsequently dispersed throughout Atlantic Canada and into Quebec with a notably high proportion of detected infections in terrestrial mammals. This strain seemed to go largely undetected elsewhere over subsequent months before causing a human fatality in Washington State in November 2025. In addition to viral zoonoses, wildlife are also reservoirs for antimicrobial-resistant bacteria. We used a culture-based approach to isolate antimicrobial-resistant E. coli from wild birds, followed by phenotypic and genomic characterization of isolated strains. Wild birds were found to be reservoirs of genetically diverse antimicrobial-resistant and potentially pathogenic E. coli. Strains isolated from birds with greater use of anthropogenically affected environments were more diverse, had higher rates of resistance, and were resistant to more compounds than those from birds that use more pristine environments. The studied bird species make significant local and migratory movements and likely serve as important vectors for the dissemination of these bacteria across broad geographic scales.