Highly Pathogenic Avian Influenza Virus Spreads Across Weddell Sea
Penguins in Antarctica. X/ @CSIC
February 14, 2025 Hour: 9:36 am
The virus has been found in 42 animals including crabeater seals, skuas, gulls, pigeons, Adélie penguins and gentoo penguins.
The highly pathogenic avian influenza virus (HPAI H5N1), detected a year ago in penguins, Antarctic pigeons, and sea lions, continues to spread throughout the southern region and has now infected all studied species on six islands in the Weddell Sea.
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This discovery was made by a scientific expedition led by Antonio Alcami, a research professor at the Spanish National Research Council (CSIC) at the Severo Ochoa Molecular Biology Center (CBMSO-CSIC-UAM). He first detected the presence of the virus in Antarctica exactly one year ago.
The CSIC-UNESPA scientific expedition, which has been monitoring the presence of this virus in Antarctica since January, has confirmed that it is now present in all species across six islands in the Weddell Sea. The virus has been found in 42 animals: in 28 carcasses of species such as the crabeater seal, skuas, gulls, Antarctic pigeons, Adélie penguins, and Gentoo penguins, as well as in 14 live individuals, including skuas and Adélie and Gentoo penguins.
“The viral load in the dead animals was very high, indicating a risk of exposure to the virus in the proximity of the carcasses,” Alcami said, adding that this discovery will enable national polar programs to prepare and consider measures to prevent human-mediated transmission of the infection and, most importantly, to avoid human contagion.
Many of the locations where the virus has been detected are frequently visited by tourist and research vessels. The researchers have also identified the HPAI virus in penguin colonies through air sampling using a pump connected to a nanofiber filter developed by CSIC. “These results indicate that air sampling is a valid methodology for detecting the virus without the need to handle animals,” Alcami emphasized.
The team found it particularly significant that the highly pathogenic avian influenza virus was present in penguin colonies that appeared to be healthy. This suggests that the infection may be spreading in colonies without causing high mortality rates.
“We do not know whether the penguins were exposed to the virus last year and have developed protective immunity or if they are more resistant than we expected,” Alcami stated, noting that the most striking case is that of Tay Head (Joinville Island), where the virus prevalence is particularly high. In this area, the infection has especially affected crabeater seals with great severity.
A Six-Week Expedition
After conducting sampling in seven areas of the Weddell Sea—including Devil, Beak, Beagle, and Heorina Islands—the CSIC-UNESPA expedition will head south of the Antarctic Peninsula to study new areas and better understand the virus’s spread. Their goal is to develop a comprehensive study on the virus’s distribution.
The scientific expedition will spend six weeks analyzing the pathogen’s presence in the Antarctic Peninsula, the South Shetland Islands, and the Weddell Sea. These studies are being conducted aboard the Australis, a sailboat capable of reaching difficult-to-access locations.
The team consists of three crew members and eight scientists of various nationalities and disciplines, including wildlife veterinarians, virologists, and molecular biologists.
The project, supported by the Spanish Polar Committee, will allow Spanish researchers to continue leading international studies on avian influenza detection in Antarctica.
The Virus in Antarctica
The highly pathogenic H5N1 strain of the avian influenza virus initially evolved in domestic poultry but has now spread among wildlife.
Since 2020, its transmission has caused significant mortality in wild birds and mammals worldwide. In 2022, its arrival in South America was confirmed.
Its anticipated expansion into Antarctica was first confirmed on February 24, 2024, thanks to discoveries made by CSIC researchers Ángela Vázquez and Antonio Alcamí. Since then, researchers have been working to determine the virus’s spread and impact in Antarctica.
teleSUR/ JF
Source: EFE