Avian flu from the north threatens Antarctic bird life | Polarjournal
One of the bird species that could bring the highly contagious H5N1 avian influenza virus from the north is the Arctic tern, which migrates toward Antarctica every northern autumn, making one of the longest documented animal migrations. Image: Dr Michael Wenger

In today’s globalized world, we are all connected and can also reach basically every corner of the globe. But we are not the only long-distance migrators. Many species, such as seabirds, travel long distances each year between their wintering and summering grounds. And, as with us, this also creates the risk that such migrations can spread uninvited guests. While we have just experienced this again with the Sars-CoV virus, another virus that has already ravaged the northern hemisphere this year is threatening the abundant bird life of Antarctica.

The name of the virus, of which the experts of the national Antarctic research programs are afraid, is unspectacularly HPAI H5N1 (engl. highly pathogenic avian influenza virus H5N1). This virus has caused mass bird deaths in numerous countries in the northern hemisphere this year, even in the Arctic. With the start of the Antarctic research and tourist season, experts within SCAR (Scientific Committee on Antarctic Research) now fear that it is only a matter of time before the virus finds its way to Antarctic bird colonies as well. Therefore, the already strict biosecurity guidelines and rules were revised and a list of additional measures and rules was issued that all visitors, whether on research stations or on ships, are expected to follow.

Some of the bird life between the Falkland Islands and Antarctica is unique, and numerous endemic species are found on the islands, such as the Falkland carcarcara. Such scavengers are particularly at risk if they eat infected animals. Image: Dr Michael Wenger

Normally, avian influenza virus infections do not result in large outbreaks in wild bird populations because the viruses have low pathogenicity. However, mutations created different subtypes of the virus in poultry farms. This includes the now rampant HPAI H5N1 virus, which made headlines several times this year as authorities in some countries had to order mass slaughter of poultry due to infections with the highly contagious virus. Unfortunately, wild bird populations have also been affected by the infections, especially geese and ducks, gull and tern species as far north as the Arctic regions of Canada and Svalbard. However, many species and colonies were also affected along the Atlantic and Pacific coastal regions, and with the onset of southward migrations, the virus may find its way toward the subantarctic islands and Antarctica. Since transmission is relatively easy via the fecal-oral route (e.g. drinking water contaminated with feces) and birds in colonies sit close together for a long time, the virus can spread like wildfire in colonies. And because deaths among harbor and grey seals in the U.S. and Canada this year have been linked to the HPAI H5N1 virus, Antarctic seals near colonies could also become infected, experts fear.

While the HPAI H5N1 virus is relatively harmless to humans, they themselves can introduce the virus into colonies as carriers. Therefore, visits to bird colonies, especially penguin colonies, are subject to particularly strict rules this season and next. Image: Dr Michael Wenger

The virus currently poses little danger to humans. Although a few hundred deaths have been recorded worldwide since the first appearance of the HPAI H5N1 virus in 2003, these have not involved human-to-human transmission and have occurred only after very close and prolonged contact. Nevertheless, humans as carriers can introduce the virus into colonies. To minimize this risk in the coming years, experts developed an expanded catalog of rules of conduct and measures that will be applied during visits to Antarctica starting this season: increased cleaning of equipment before visits and a possible increase in the distance to animals are among them, as well as the wearing of face masks, protective glasses and gloves by researchers who have contact with the animals, whether alive or dead. Also, refrain from lying on the ground to take pictures.

In addition, colonies should first be checked by experts or specially trained guides before visits to see if birds and the colonies show signs of infection. To this end, experts list signs such as loss of balance, trembling of the head and body, lethargy, and also sudden mass mortality. If such an observation is made, the visit to the colony should be cancelled and the site should be reported to the authorities immediately. Fortunately, however, no outbreaks have been reported to date. However, the first ships with tourists and researchers and have now arrived on the islands and in Antarctica, and it is to be hoped that the bird life in Antarctica will not have to go through the same thing as we have in recent years.

Dr Michael Wenger, PolarJournal

Link to the guidelines and recommendations

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