image: Image of the Australis sailing ship in Antarctica
Credit: Antonio Alcamí (CBMSO)
The CSIC-UNESPA scientific expedition has been underway since last January with the aim of monitoring the presence of the highly pathogenic avian influenza virus (HPAI H5N1) in Antarctica. The first results of the campaign, led by Antonio Alcamí, a CSIC research professor at the Severo Ochoa Molecular Biology Center (CBMSO-CSIC-UAM), have confirmed the presence of the virus in all species detected on six islands in the Weddell Sea, Antarctica.
This positive result was obtained in 42 animals, including 28 carcasses of species such as crabeater seals, skuas, gulls, snowy sheathbill, Adélie penguins, and Gentoo penguins, as well as 14 live individuals of 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 to the carcasses,” explains Alcamí.
The finding, according to the researcher, will allow national polar programs to be prepared and to consider measures to prevent the transmission of the infection through human means, especially the spread to people, as many of the locations where the virus was detected are frequently visited by tourist and research vessels.
The presence of the HPAI (Highly Pathogenic Avian Influenza) virus was confirmed through multiple laboratory tests, including specific PCRs for influenza virus and the H5 subtype, followed by sequencing of the protease cleavage region, which defines the presence of the HPAI virus with 100% certainty. “We performed PCR tests on swab samples to identify the virus M and H5 genes. Subsequently, the presence of the virus was confirmed by sequencing using the Oxford Nanopore technology.”
Additionally, the researchers identified the HPAI virus in penguin colonies through air sampling. “We collected air samples with a pump connected to a nanofiber filter developed by CSIC, which captures the virus. PCR tests on the filter confirmed the detection of the pathogen. These results indicate that air sampling is a valid method for detecting the virus without the need to handle animals,” highlights the CBMSO researcher.
Of particular significance is the presence of highly pathogenic avian influenza in apparently healthy penguin colonies. Its detection in live Adélie and Gentoo penguins suggests that the infection may be spreading in colonies without causing significant mortality. “We do not know if the penguins were exposed to the virus last year and have protective immunity or if they are more resistant than expected.”
Geographically, the most notable case is Tay Head (Joinville Island), where the virus prevalence is particularly high. In this area, the infection has severely affected crabeater seals.
After sampling seven areas of the Weddell Sea (including Devil, Beak, Beagle, and Heroína islands), the CSIC-UNESPA Antarctic Expedition will move south of the Antarctic Peninsula to study new areas and gain a better understanding of the virus's spread. “Our goal is to conduct a comprehensive study of the virus’s distribution,” concludes Antonio Alcamí.
Research aboard the Australis yacht
The scientific expedition led by CSIC and funded by a hundred insurance companies affiliated with UNESPA, the Spanish insurance business association, is analyzing the presence of the pathogen over six weeks in the Antarctic Peninsula, the South Shetland Islands, and the Weddell Sea. This work is being carried out aboard the Australis sailboat, a vessel with extensive experience navigating Antarctica. It allows access to difficult-to-reach locations and is equipped with the most modern satellite navigation and communication systems. The facilitating role of the General CSIC Foundation has been crucial in securing access to this vessel and other essential resources for the expedition.
The team is made up of three crew members and eight scientists from different nationalities and disciplines, including veterinarians specializing in wildlife, virologists, and molecular biologists. A real-time PCR molecular diagnostic and virus sequencing laboratory has been installed on the sailboat, enabling the team to diagnose cases quickly. Additionally, all samples collected during the expedition are obtained following strict safety protocols.
The project, supported by the Spanish Polar Committee, will allow Spanish research to continue leading international studies on the detection of avian influenza in Antarctica.
The evolution of the virus in Antarctica
The highly pathogenic H5N1 strain of the avian influenza virus initially evolved in domestic poultry but recently adapted to spread among wildlife. Since 2020, its spread has caused significant mortality among wild birds and mammals worldwide, and in 2022, its arrival in South America was confirmed.
Its expected spread to Antarctica was first confirmed on February 24, 2024, thanks to discoveries by CSIC researchers Ángela Vázquez and Antonio Alcamí. In March 2024, the results of the HPAI Australis Expedition, involving Begoña Aguado and Antonio Alcamí, revealed the spread of highly pathogenic avian influenza virus in the Antarctic Peninsula, where high mortality levels in skua birds were observed.
In July, this discovery was followed by the confirmation of the virus’s presence in Antarctica for the first time in a marine mammal. Since then, researchers have been working to determine the virus’s spread and impact in Antarctica.
The current project involves the Severo Ochoa Molecular Biology Center (CBMSO, CSIC-UAM); the Faculty of Veterinary Medicine and Animal Science of the University of São Paulo (Brazil); the Aquatic Mammals Institute (Brazil); the Karen C. Drayer Wildlife Health Center, a program of the University of California-Davis’s Faculty of Veterinary Medicine (USA); and Ocean Expeditions (Australia).
CSIC Communication
Method of Research
News article
Subject of Research
Animals