By Lehlohonolo Lehana.
The Department of Forestry, Fisheries and the Environment (DFFE) has confirmed the highly pathogenic avian influenza (HPAI) on Marion Island, South Africa’s sub-Antarctic outpost.
The confirmation follows months of suspected cases after test samples were transported to mainland South Africa, via the SA Agulhas II, in February 2025.
In March, Polymerase Chain Reaction (PCR) testing confirmed infection in six bird species, comprising Wandering Albatross (Diomedea exulans), King Penguin (Aptenodytes patagonicus), Brown (Subantarctic) Skua (Stercorarius antarcticus), Southern Giant Petrel (Macronectes giganteus), Northern Giant Petrel (M. halli) and Sooty Albatross (Phoebetria fusca), the department said.
The first signs of trouble, however, emerged in mid-September 2024, when a brown skua exhibiting neurological symptoms raised suspicions among observers.
More similar cases were reported in early November and mortalities in multiple species have continued into March 2025, though the overall death rate slowed significantly in January.
“The reduced mortality rate is promising, but 31 bird species breed on Marion Island and the bird species and age composition varies throughout the year, therefore it is difficult to predict how the outbreak will progress, explained the DFFE’s.
Located in the Southern Ocean 1,700km southeast of Cape Town, Marion Island is part of the Prince Edward Islands group, a globally important nesting ground for millions of seabirds. Among its inhabitants are the world’s largest breeding population of wandering albatrosses, as well as vast populations of penguins, southern giant petrels, brown skuas and seals.
“Observations of and laboratory test results for HPAI (H5N1) on Marion Island can assist in inferring the potential risk to animals on Prince Edward Island, since they share various ecological characteristics, added the department.”
“Having spread around the globe since 2021, HPAI (H5N1) was detected in seabirds and marine mammals in South Georgia, southeast of South America, in October 2023. It reached the Antarctic Peninsula in February 2024 and was detected at the French archipelagos of Crozet and Kerguelen (950 and 2300 km east of Marion respectively) in October and November 2024.
The virus can be transported long distances by migrating birds, and the virus moved from South Georgia to the French islands.
“The situation on Marion Island is being closely monitored by the field personnel overwintering on the island, who have been trained to recognise possible HPAI signs in birds and seals, and in the necessary monitoring and mitigation methods. They will continue to take all precautions to ensure they do not spread the virus. There are few other disease mitigation tools available in this type of situation, concluded the department.”