The bird flu It is a disease that is on the lips of many people in Spain right now due to the great impact is having on our birds, causing many pens to have to be confined. But a variant of this virus is also wreaking havoc in Antarctica, causing the death of thousands of sea seals.
A broken sanctuary. Antarctica was a frozen and impenetrable sanctuary, until now. The highly pathogenic H5N1 virus, a variant of avian flu, is arriving on the subantarctic coasts to stay. And it has done so by causing a “massacre” according to the scientists themselves, which have determined the death of 50% of reproductive female elephant seals from the south on the island of South Georgia.
The discovery, led by the British Antarctic Survey (BAS), is not just a tragic figure; It is confirmation that the virus has found a new and effective transmission vector: marine mammals and not just birds.
How it was revealed. Quantifying mortality in colonies as dense as this one in South Georgia is not easy. And we are precisely talking about the home of the largest population of sea seals, making counting them a titanic and risky task. This is where technology comes in.
The Bamford team used drones to fly over breeding beaches. Comparing population density before and after the arrival of the virus, they documented a loss of half of adult females. This non-invasive method has been key to obtaining accurate data without interfering in an already devastated ecosystem.
It is not isolated. What is happening in South Georgia is the chronicle of a death foretold. This event is the continuation of the “first wave” that hit Argentine Patagonia.
A previous study, published in Nature Communicationswas the first to set off all the alarms. This work not only confirmed the jump of the virus from birds to elephant seals, but also demonstrated what the scientific community feared most: sustained transmission between mammals.
The ideal breeding ground for this virus were the elephant seals that live crowded on the beaches during the breeding season, they became a perfect breeding ground. The virus no longer needed birds to spread.
Out of control. In this way, the H5N1 has become a panzootiathat is, an animal epidemic on a planetary scale. Although the media focus right now is on Antarctic mammals, and in Spain on poultry, the reality is that we are talking about a much bigger problem.
According to the latest report from the World Organization for Animal Health, the virus is already has affected more than 150 million birds in 84 countries, either by direct death or by the emergency sacrifices necessary to contain it.
To monitor this serious problem, the Scientific Committee for Antarctic Research (SCAR) maintains an updated database that centralizes all detections of HPAI in Antarctic fauna.
And the risk in humans? It is the inevitable question. If the virus has learned to jump from birds to mammals and transmit efficiently between them (as happens in seals and elephant seals), are we humans next?
The latest risk assessment from WHO, FAO and WOAH keep calmbut with nuances. Right now, the risk to the general human population is still considered ‘low’. However, the report warns that this is an infection that should be closely monitored as it provides the virus the opportunity to better adapt to hosts.
In short, every seal that becomes infected in the Arctic is a new probability that the virus ends up mutating and that it finally becomes a major security problem for everyone.
Images | Yuriy Rzhemovskiy Fusion Medical Animation
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