Name
Isolation and Molecular Characterization of West Nile Virus Circulating in Wild Bird Populations in Quebec
Presenter
Anais Rasquier Zevallos, INRS
Co-Author(s)
Anaïs Rasquier1, Yago C. P. Gomes1, Chris J. Neufeldt3, Stéphane Lair2, Carl Gagnon2 and Laurent Chatel-Chaix1 1 Centre Armand-Frappier santé Biotechnologie, Institut national de la recherche scientifique, Laval, Québec, Canada 2 Centre de diagnostic vétérinaire de l'Université de Montréal, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada. 3 Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA.
Abstract Category
Discovering & Evolving
Abstract
West Nile Virus (WNV) is an arbovirus transmitted by mosquitoes and maintained in nature through infected wild birds, which act as reservoirs. It is endemic in several regions worldwide, including Eastern Canada, and infection in humans can cause severe encephalitis and meningitis, leading to fatal outcomes. Despite its global impact, no vaccines or antiviral treatments are currently available. Monitoring the evolution of WNV in wildlife is critical to identify potential changes that could increase risks to human health. This study aims to isolate and characterize WNV strains circulating in wild bird populations in Quebec. WNV-positive tissues collected in 2023–2024 were used to isolate and amplify viruses under biosafety level 3 conditions. Replication kinetics were compared to the NY99 reference strain in mosquito (C6/36), human (Huh7.5 and A549), and avian (DF-1) cell lines to assess viral fitness across vector and vertebrate hosts. Overall, isolates exhibited replication kinetics comparable to NY99. However, C6/36 cells showed delayed replication with higher titers at days 2–3, together with reduced induction of antiviral genes compared to human and avian cells. Viral replication and host innate immune responses were monitored using plaque assays, RT-qPCR, and immunofluorescence. Viral RNA sequencing identified lineage 1a strains containing polymorphisms in non-structural regions of the polyprotein. Selected mutations will be introduced into a lineage 2 WNV GFP-reporter replicon to assess their impact on viral RNA replication and innate immune modulation. Ultimately, this study will determine whether newly acquired polymorphism circulating in Quebec influence viral replication and thus, potentially human health.