Abstract Title
Spread of H5N1 marine mammal clade viruses (genotype B3.2) among coastal wildlife in Chubut, Argentina, 2023-2024.
Abstract
The highly pathogenic avian influenza virus H5N1 (clade 2.3.4.4b, genotype B3.2) was first introduced into Argentina in February 2023 via the northern region. It spread southward across 17 provinces, causing 94 outbreaks in poultry and only 7 in waterfowl in inland Argentina. The outbreaks ceased by July. However, the virus re-emerged in August 2023, this time entering through the southern tip of coastal Argentina (Tierra del Fuego province) and spreading northward along the Atlantic coast, causing severe outbreaks in marine mammals from August to October. Although the number of seabirds affected by the virus remained relatively low during the initial spread in marine mammals in Argentina, from October on we detected an increase in the number of both individuals and species affected, with a predominant impact on terns. Here, we report the full genome characterization of novel H5N1 strains detected in sea lions (n=2) and six seabird species (n=17), at eight sites along > 600 km of coastline in Chubut province, between October 2023 - February 2024. All virus strains belonged to the clade that circulated broadly among marine mammals across five South American countries, likely via mammal-mammal transmission. Importantly, the data show that these marine mammal clade H5N1 viruses were also able to spread between wild birds for 5 months, with little evidence of reversion at the mammalian adaptive sites previously observed in pinnipeds. This finding highlights the need for increased surveillance and research collaboration to further determine the true spread and host range of H5N1 in South America.
Co-Author(s)
Agustina Rimondi1,2, Ralph E. T. Vanstreels3, Martha I. Nelson4, Valeria Olivera2, Luciana Gallo5,6, Flavio Quintana5, Martin I. Brogger5, Alexis Durant3, Agustina Donini7, Julieta Campagna8, Victoria Zavattieri8, Claudio Campagna8, Valeria Falabella8, Thorsten Wolff1, Marcela Uhart3
1 Robert Koch Institute Unit 17, Berlin, Germany
2 Instituto de Virología e Innovaciones Tecnológicas, INTA-CONICET, Buenos Aires, Argentina
3 Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, USA
4 National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, USA
5 Instituto de Biología de Organismos Marinos, CONICET, Chubut, Argentina
6 Coordinación Regional de Inocuidad y Calidad Agroalimentaria, SENASA, Puerto Madryn, Chubut, Argentina.
7 Southern Right Whale Health Monitoring Program, Puerto Madryn, Argentina
8 Wildlife Conservation Society, Argentina Program, Buenos Aires, Argentina
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds