Distribution patterns of highly pathogenic avian influenza virus in Canadian murres

Viral monitoring in wildlife as typified by highly pathogenic avian influenza virus (HPAIV) in seabirds. Image from facets-2023–0185.

Migratory seabirds are reservoirs and intercontinental vectors for avian influenza virus (AIV).

Historically, wild birds have mostly harbored low pathogenic avian influenza virus (LPAIV) subtypes, but increasingly they have demonstrated susceptibility to highly pathogenic avian influenza virus (HPAIV) since the emergence of H5N1 lineage A/goose/Guangdong/1/1996 (Gs/GD), a new clade of which has led to global widespread morbidity and mortality in wild and domestic animals since 2021.

Among the many migratory seabirds that can act as HPAIV hosts, murres (Uria spp.) are of particular importance to monitor because they are abundant, harvested for human consumption, migrate across ocean basins, and are known AIV reservoir hosts.

Read this open access paper on the FACETS website.

We analyzed historical and new AIV testing data from murres sampled in the Canadian Atlantic, Arctic, and Pacific basins to calculate the frequency of disease (period prevalence) for multiple years, seasons, and regions.

There were spatiotemporal differences in the prevalence of LPAIV and HPAIV in live/harvested and found dead murres sampled in Canada.

Prior to 2021, HPAIV had not been detected in murres. In 2022, HPAIV prevalence in the Atlantic region was high, especially during the summer breeding season, while in the Arctic, HPAIV was only detected once, but LPAIV prevalence was higher than any previous years.

Ongoing monitoring of AIV trends in murres and other wild bird species will ensure that we can identify significant changes and mitigate potential public health risks.

Based on observed prevalence in 2022, we recommend that approximately 100 samples be collected from each site annually to detect moderate 25% additive increases in AIV or HPAIV prevalence in the future.

Read the paper — Spatiotemporal patterns of low and highly pathogenic avian influenza virus prevalence in murres in Canada from 2007 to 2022 — a case study for wildlife viral monitoring by Angela McLaughlin, Jolene Giacinti, Ishraq Rahman, Jordan Wight, Kathryn Hargan, Andrew S. Lang, Mark L. Mallory, Gregory J. Robertson, Kyle Elliot, Davor Ojkic, Stéphane Lair, Megan Jones, Yohannes Berhane, Grant Gilchrist, Laurie Wilson, Sabina I. Wilhelm, Michael G.C. Brown, and Jennifer F. Provencher.