Penguin tests positive for bird flu but shows no symptoms

Clade 2.3.4.4b of H5N1 avian influenza viruses has spread rapidly across continents since 2020, representing one of the worst outbreaks of the disease in recent years. In November 2023, scientists first warned of the virus’s arrival in Antarctica and its possible impact on the continent’s ecosystems. But now, according to a study, there may be relatively good news.

It was not until 2023 that the H5N1 pathogen was reported in Antarctica. The Antarctic region includes the ice shelves, waters and all island territories of the Southern Ocean located within the Antarctic Convergence Zone, a band of ocean surrounding Antarctica with which the Antarctic waters are found. The subantarctic regions are warmer. On September 17, researchers from the British Antarctic Survey (BAS) discovered a southern giant petrel (a seabird) exhibiting loss of coordination, neurological tics, and lethargic behavior on Bird Island, South Georgia. This is the beginning.

On October 8, Brown Skua (also known as Falkland Shearwater, Antarctic Spear), at the same location, the men showed lethargy, neck twitching, convulsions and an inability to fly, and by October 10 the men were dead. “Several resident birds, including the wandering albatrosses (Isophylla), Macaroni Penguin (red-bellied locust), Grey-headed Albatross (Chrysostomia seaweed) and white-chinned petrel (Prototheca hirata), are classified as vulnerable or endangered. Iconic long-lived, late-maturing species such as albatrosses have little resistance to rapid increases in population mortality. Outbreaks of high-mortality diseases therefore pose a significant threat to already vulnerable seabird populations,” the researchers warned at the time.

Recently, researchers traveled to 13 seabird breeding grounds on the east and west coasts of the Antarctic Peninsula and the west coast of Antarctica between December 2023 and January 2024. A total of 115 birds of four species were captured, sampled and released. Of the 115 individuals sampled, 9 tested positive, including 8 Adélie penguins and 1 Antarctic cormorant, equivalent to a positive rate of approximately 12% for all Adélie penguins sampled. None of the birds sampled, including suspected cases, showed any symptoms.

“Although the positivity rate among Adélie penguins on Beagle Island was approximately 50%, birds potentially infected with HPAIV H5N1 did not show clinical signs and sampling sites did not experience excessive mortality, which increases the risk for some seabirds The possibility that species may be more susceptible to infection with HPAIV H5N1. As previously reported by Chilean authorities in Humboldt and Magellanic penguins, they are more susceptible to H5N1 infection than other penguins, the scientists wrote in a study that has not yet been peer-reviewed. . (can be seen: An ecological perspective on “La Vorágine” one hundred years later)

Researchers say this is partly positive. Of course, this may seem particularly peaceful to those penguins, “but it has strong implications for Antarctic wildlife as a whole, which could lead to widespread and unintentional spread of the virus, as asymptomatic carriers may act as a ‘Trojan horse.'” Promoting HPAIV introduction and dissemination. Previously unaffected populations, they write, ended up contaminating more susceptible species (such as pinnipeds, which have been decimated by highly pathogenic avian influenza in South America and South Georgia).

Basically, they believe that asymptomatic HPAIV carriers may act as a “Trojan horse,” allowing the virus to inadvertently enter and spread into previously unaffected wildlife populations. “These new findings highlight the urgent need to monitor and address emerging diseases in vulnerable Antarctic seabirds. “Implementing strict biosecurity measures during Antarctic activities is critical to minimizing the potential spread of avian influenza. ” (can be seen: 270 million-year-old amphibian fossil discovered)

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