Pathogen Surveillance in Swallows (family Hirundinidae): Investigation into Role as Avian Influenza Vector in Eastern Canada Agricultural Landscapes

Jennifer F Provencher; Michael G C Brown; Kathryn Hargan; Andrew S Lang; David Lapen; Hannah Lewis; Mark L Mallory; Rebecca Michelin; Greg W Mitchell; Ishraq Rahman; Chris Sharp; Stephen Shikaze; Jordan Wight

doi:10.7589/JWD-D-23-00167

Pathogen Surveillance in Swallows (family Hirundinidae): Investigation into Role as Avian Influenza Vector in Eastern Canada Agricultural Landscapes

J Wildl Dis. 2024 Apr 26. doi: 10.7589/JWD-D-23-00167. Online ahead of print.

Authors

Affiliations

¹ Environment and Climate Change Canada, Science and Technology Branch, National Wildlife Research Centre, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1A 0H3, Canada.
² Environment and Climate Change Canada, Canadian Wildlife Service, Wildlife Management and Regulatory Affairs Division, 351 Boulevard Saint-Joseph, Gatineau, Québec J8Y 3Z5, Canada.
³ Department of Biology, Memorial University of Newfoundland, 45 Arctic Avenue, St. John's, Newfoundland and Labrador A1C 5S7, Canada.
⁴ Ottawa Research Development Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6, Canada.
⁵ Environment and Climate Change Canada, Canadian Wildlife Service, Ontario Region, 335 River Road, Ottawa, Ontario K1V 1C7, Canada.
⁶ Department of Biology, Acadia University, 15 University Drive, Wolfville, Nova Scotia B4P 2R6, Canada.

PMID: 38666308
DOI: 10.7589/JWD-D-23-00167

Abstract

First detected in Atlantic Canada in December 2021, highly pathogenic avian influenza virus (HPAIV) subtype H5N1 clade 2.3.4.4b, A/Goose/Guangdong/1/96 lineage, has caused massive mortality in wild birds and domestic poultry in North America. Swallows (Hirundinidae), abundant in North American agricultural ecosystems, have been proposed as possible (bridge) species for HPAIV transmission between wild and domestic birds. We aimed to seek evidence of the potential role of swallows in bridging AIV infection between wild bird reservoirs and poultry flocks in eastern Canada. During a wide-scale outbreak of HPAIV in wild birds and poultry farms across eastern Canada, 200 samples were collected from swallow breeding sites in the Canadian provinces of New Brunswick, Nova Scotia, Ontario, and Quebec, June-August 2022. Samples came from Barn Swallow (Hirundo rustica; n=142), Tree Swallow (Tachycineta bicolor; n=56), and Cliff Swallow (Petrochelidon pyrrhonota; n=2) nests. All samples tested negative for AIV, suggesting that HPAIV and low pathogenic AIV (LPAIV) strains were probably not circulating widely in swallows during the 2022 breeding season in eastern Canada; thus swallows may present a low risk of transmitting AIV. Within a management context, these findings suggest that removing nests of Barn Swallows, a species at risk in Canada, from the exterior of biosecure domestic poultry facilities may not significantly reduce risks of HPAI transmission to poultry.

Keywords: Bridge host; RT-PCR; environmental surveillance; highly pathogenic avian influenza virus; poultry; species at risk.