Investigating high pathogenicity avian influenza virus (HPAIV) incursions to remote islands
Detection of H5N1 on Gough Island in the South Atlantic Ocean.
20 February 2026, Emerging Microbes and Infections
Summary
Gough Island: seabird capital of the world
Gough Island, a volcanic landmass in the central South Atlantic Ocean has been nicknamed the seabird capital of the world, providing habitats for over 22 species of birds and several pinniped species. This remote, subantarctic island is a UNESCO-protected site of substantial conservational importance.
Isolation of HPAIV H5N1 in Tristan Skuas
In September 2024, HPAIV H5N1 clade 2.3.4.4b was isolated from three Tristan skua (Stercorarius antarcticus hamiltoni ) carcasses on Gough Island. To investigate potential incursion routes, a combined approach was employed, incorporating genomic analyses with year-round tracking data from global location sensors.
Originally, migratory movement patterns suggested southern Africa as the most obvious pathway, however the strain detected on Gough Island was found to be more closely related to that previously identified in South Georgia in October 2023.
This indicated that infection may have occurred during the pre-laying exodus, when skuas disperse into frontal waters south of the island.
Role of migratory seabirds in HPAIV transmission
Migratory seabirds, such as skuas, play a significant role in the transmission of HPAIV over long distances. These birds act as both reservoirs and vectors and have been linked to multiple outbreaks since 2021.
Surveillance strategies and biosecurity measures
The detection of HPAIV H5N1 in skuas on Gough Island highlights the importance of continued vigilance, proactive and geographically inclusive surveillance strategies, and application of global biosecurity measures.
Migration routes of Gough Island skuas
Figure 1. (adapted from Figure 4 in text) panels (b) and (c) illustrate individual skua migration routes from the Gough Island region to non-breeding foraging grounds on the South African and Namibian continental shelves, and the corresponding return migrations, respectively. The solid bold red line denotes the movement of one individual (GLS tag BH142) that tested positive for highly pathogenic avian influenza virus (HPAIV) in 2024.