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Nat Commun
. 2026 Apr 7.
doi: 10.1038/s41467-026-71544-3. Online ahead of print.
Genomic analysis of high pathogenicity avian influenza viruses from Antarctica reveals multiple introductions from South America
Maria Ogrzewalska 1 , Ralph Eric Thijl Vanstreels 2 , Elisa Cavalcante Pereira 3 , Emandi Campinas 3 , Leonardo Correa Junior 3 , Jennifer Oliveira Melo 3 , Larissa Macedo 3 , Luciana Reis Appolinario 3 , Ighor Arantes 4 , Martha Lima Brandao 5 , Bruno Rocha Pribul 6 , Claudio Marcos Rocha 6 , Fabricio Souza Campos 7 8 , Ueric José Borges de Souza 8 , Bruna Paredes Galarza 7 , Alanis Silva Melgarejo 7 , Luciana Trilles 9 , Lucas Machado Moreira 5 9 , Wim Degrave 10 , Maithê Magalhães, Daniel Moreira 10 , Roberto do Val Vilela 11 , Fernando Couto Motta 3 , Marilda M Siqueira 3 , Paola Cristina Resende 12
Affiliations
The spread of high pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b into Antarctica poses a major threat to polar wildlife. We report the detection of H5N1 in carcasses of eight species during the 2023-2024 and 2024-2025 austral summers in the South Shetland Islands: Antarctic shag, Antarctic tern, kelp gull, pintado petrel, Antarctic petrel, skuas, Antarctic fur seal, and southern elephant seal. Whole-genome sequencing, mutational profiling, and phylogenetic reconstruction revealed that the viruses detected in these hosts descended from distinct introduction events. One group of strains including complete and partial viral genomes from a gull, skuas, fur seals, an Antarctic tern, and a southern elephant seal clustered with H5N1 strains previously detected in marine mammals in South America and formed a polyphyletic lineage consistent with at least two independent introductions into Antarctica. A second group of strains including complete and partial viral genomes from petrels, shags, and skuas clustered with H5N1 strains previously detected in seabirds and marine mammals in South Georgia and with a previously reported HPAIV detection from Torgersen Island, Antarctic Peninsula. These findings reveal extensive epidemiological connectivity between South America and Antarctica, with South Georgia serving as a "stepping stone" for virus spread in the region.
. 2026 Apr 7.
doi: 10.1038/s41467-026-71544-3. Online ahead of print.
Genomic analysis of high pathogenicity avian influenza viruses from Antarctica reveals multiple introductions from South America
Maria Ogrzewalska 1 , Ralph Eric Thijl Vanstreels 2 , Elisa Cavalcante Pereira 3 , Emandi Campinas 3 , Leonardo Correa Junior 3 , Jennifer Oliveira Melo 3 , Larissa Macedo 3 , Luciana Reis Appolinario 3 , Ighor Arantes 4 , Martha Lima Brandao 5 , Bruno Rocha Pribul 6 , Claudio Marcos Rocha 6 , Fabricio Souza Campos 7 8 , Ueric José Borges de Souza 8 , Bruna Paredes Galarza 7 , Alanis Silva Melgarejo 7 , Luciana Trilles 9 , Lucas Machado Moreira 5 9 , Wim Degrave 10 , Maithê Magalhães, Daniel Moreira 10 , Roberto do Val Vilela 11 , Fernando Couto Motta 3 , Marilda M Siqueira 3 , Paola Cristina Resende 12
Affiliations
- PMID: 41942444
- DOI: 10.1038/s41467-026-71544-3
The spread of high pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b into Antarctica poses a major threat to polar wildlife. We report the detection of H5N1 in carcasses of eight species during the 2023-2024 and 2024-2025 austral summers in the South Shetland Islands: Antarctic shag, Antarctic tern, kelp gull, pintado petrel, Antarctic petrel, skuas, Antarctic fur seal, and southern elephant seal. Whole-genome sequencing, mutational profiling, and phylogenetic reconstruction revealed that the viruses detected in these hosts descended from distinct introduction events. One group of strains including complete and partial viral genomes from a gull, skuas, fur seals, an Antarctic tern, and a southern elephant seal clustered with H5N1 strains previously detected in marine mammals in South America and formed a polyphyletic lineage consistent with at least two independent introductions into Antarctica. A second group of strains including complete and partial viral genomes from petrels, shags, and skuas clustered with H5N1 strains previously detected in seabirds and marine mammals in South Georgia and with a previously reported HPAIV detection from Torgersen Island, Antarctic Peninsula. These findings reveal extensive epidemiological connectivity between South America and Antarctica, with South Georgia serving as a "stepping stone" for virus spread in the region.