Keywords
wild birds
viral surveillance
Beagle Channel
sub-Antarctic Magellanic ecoregion
How to Cite
Abstract
Avian influenza viruses (AIVs) are important pathogens in wild aquatic birds worldwide, however, their presence in sub-Antarctic regions remains largely unknown. To address this gap, we report surveillance data from the Cape Horn Biosphere Reserve, in southernmost Chile, for the austral reproductive seasons of 2024–2025. In total, 352 fecal samples were collected from coastal sites, islets, and passerines in long-term monitoring programs. Only one environmental sample obtained at Punta Gusano in January 2024 tested positive by real-time RT-PCR (Ct 36.78), giving a detection rate of 0.625%, while all passerine and 2025 season samples were negative. This single weak positive result suggests occasional virus introduction, but there is no evidence of sustained circulation. The result agrees with previous reports showing active AIV dynamics in northern and central Chile, but very limited activity in Patagonia. The finding also matches the few confirmed highly pathogenic avian influenza H5N1 clade 2.3.4.4b cases recorded in southernmost Chile during the 2023 outbreak. Together, these observations suggest that southernmost Chile remains minimally affected by AIV. However, its proximity to Antarctica and location at a major migratory flyway intersection highlight the importance of continued surveillance in these remote ecosystems.
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Copyright (c) 2026 Fernanda Sánchez-Rodríguez, Natalia Guzmán, Juan Rivero de Aguilar, Carlos E. Valeris-Chacín, Ricardo Rozzi, Pedro Jimenez Bluhm