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Nat. Comm. - Cross-species and mammal-to-mammal transmission of clade 2.3.4.4b highly pathogenic avian influenza A/H5N1 with PB2 adaptations
Translation Google
Avian influenza affects marine mammals in Chile
Chilean scientists warn of public health risks after confirming adaptation of the H5N1 virus
May 12, 2025
By : Romina Onel
Recently, a group of scientists announced that the H5N1 avian influenza virus mutated in Chile, allowing the transmission of avian influenza among marine mammals, triggering an animal pandemic.
The study, published in the journal Nature Communications, was led by Victor Neira, a professor of Animal Virology at the Faculty of Veterinary and Animal Science at the University of Chile. He is also a spokesperson for the National One Health Commission of Colmevet.
Regarding this animal pandemic that caused the death of more than 120,000 birds and more than 40,000 sea lions in Chile, Neira recalled that "we did not have H5N1 or avian flu in South America until the end of 2022, when the first cases were detected in the north of the country. These cases spread from North America through migratory birds, causing the greatest damage in the first half of 2023."
“Before it reached South America, isolated cases of seal mortality were observed, but at the beginning of 2023, we observed a mass mortality of marine mammals in Chile, with South American sea lions being the most affected,” he explained.
The expert also explained that "we conducted a series of studies, the latest of which was the sequencing of all the viruses, which demonstrates genetic evidence that the virus was transmitted between birds and mammals, including a human."
"One of the main findings is that the virus adapted and managed to transmit among these mammals, since it was previously believed that mammals died without infecting others, which is one more step toward a virus becoming a pandemic," he emphasized.
Neira added that "we found a mutation in a PB2 gene, which is associated with an adaptation to replication in mammals."
WHAT'S HAPPENING IN THE US?
In addition, Neira reported that "in the United States, the virus was transmitted from wild birds to cows, spreading it through milk, and this has infected many people. Some cats belonging to workers on these farms have even died from the virus."
"The dynamic is different for cows, because they don't die from influenza, and since the virus replicates in the udder, it is transmitted through milking machines to other cows and other peridomestic animals that live around the dairy, which do die," he pointed out.
Regarding whether this could affect human health, Neira warned that "any infected animal could infect humans, but the most common infections occur on poultry farms."
Elaborating on this, he said, "This tells you the virus has the ability to mutate, and although wildlife is far removed from humans, it does pose a threat."
However, Neira asserted that "although the virus has already infected people, the final step for it to become a human pandemic is for it to spread from person to person."
A WARNING
When asked about this issue, Cristian Araya, a professor from the Department of Biology and an expert in fish genomes at the University of Serena, stated that "the recent discovery by Chilean scientists regarding the transmission of the H5N1 virus among mammals is not just a scientific milestone; it's a direct warning."
Araya also stated that "the fact that this virus, historically associated with birds, has managed to adapt to marine mammals on our coasts, and that there is already at least one serious human case associated with it, forces us to rethink the boundaries between animal, environmental, and human health."
"Today we're talking about a panzootic, an animal pandemic, but what's at stake goes beyond that; public health is at risk," he insisted.
Emphasizing this, the expert argued that "Chile faces the challenge of urgently integrating a One Health approach that considers the close relationship between ecosystems, animals, and people. The mass death of wildlife, coupled with potential contagion from domestic animals or contaminated food, presents us with a scenario we cannot ignore."
"This isn't about alarmism, but about anticipation. Without robust epidemiological surveillance, health education, and integrated policies, the next outbreak won't be a surprise, it will be a consequence," he concluded.
EFFECTS IN THE REGION
Regarding the current situation regarding avian influenza, Jorge Fernández, Regional Director of the Agricultural and Livestock Service (SAG), stated that "since April 2024, the Coquimbo region has been declared free of avian influenza, with the last positive case detected on July 20, 2023. Since then, we have not recorded any new outbreaks in the area."
For his part, the Regional Director of the National Service for Disaster Prevention and Response (SENAPRED) of Coquimbo, Angelo Hernández revealed that during 2023, in the region the following died from avian flu: 1,420 Humboldt penguins; 2,240 specimens of common sea lion; 128 Magellanic penguins; 20 Chungungos; 14 Southern sea lions; 10 Juan Fernández fur seals; 9 Porpoises; 1 Common dolphin and others (13).
It should be added that between 2023 and 2024, an isolated case was confirmed in a person in a region in the north of the country.
Nat. Comm. - Cross-species and mammal-to-mammal transmission of clade 2.3.4.4b highly pathogenic avian influenza A/H5N1 with PB2 adaptations
Translation Google
Avian influenza affects marine mammals in Chile
Chilean scientists warn of public health risks after confirming adaptation of the H5N1 virus
May 12, 2025
By : Romina Onel
Recently, a group of scientists announced that the H5N1 avian influenza virus mutated in Chile, allowing the transmission of avian influenza among marine mammals, triggering an animal pandemic.
The study, published in the journal Nature Communications, was led by Victor Neira, a professor of Animal Virology at the Faculty of Veterinary and Animal Science at the University of Chile. He is also a spokesperson for the National One Health Commission of Colmevet.
Regarding this animal pandemic that caused the death of more than 120,000 birds and more than 40,000 sea lions in Chile, Neira recalled that "we did not have H5N1 or avian flu in South America until the end of 2022, when the first cases were detected in the north of the country. These cases spread from North America through migratory birds, causing the greatest damage in the first half of 2023."
“Before it reached South America, isolated cases of seal mortality were observed, but at the beginning of 2023, we observed a mass mortality of marine mammals in Chile, with South American sea lions being the most affected,” he explained.
The expert also explained that "we conducted a series of studies, the latest of which was the sequencing of all the viruses, which demonstrates genetic evidence that the virus was transmitted between birds and mammals, including a human."
"One of the main findings is that the virus adapted and managed to transmit among these mammals, since it was previously believed that mammals died without infecting others, which is one more step toward a virus becoming a pandemic," he emphasized.
Neira added that "we found a mutation in a PB2 gene, which is associated with an adaptation to replication in mammals."
WHAT'S HAPPENING IN THE US?
In addition, Neira reported that "in the United States, the virus was transmitted from wild birds to cows, spreading it through milk, and this has infected many people. Some cats belonging to workers on these farms have even died from the virus."
"The dynamic is different for cows, because they don't die from influenza, and since the virus replicates in the udder, it is transmitted through milking machines to other cows and other peridomestic animals that live around the dairy, which do die," he pointed out.
Regarding whether this could affect human health, Neira warned that "any infected animal could infect humans, but the most common infections occur on poultry farms."
Elaborating on this, he said, "This tells you the virus has the ability to mutate, and although wildlife is far removed from humans, it does pose a threat."
However, Neira asserted that "although the virus has already infected people, the final step for it to become a human pandemic is for it to spread from person to person."
A WARNING
When asked about this issue, Cristian Araya, a professor from the Department of Biology and an expert in fish genomes at the University of Serena, stated that "the recent discovery by Chilean scientists regarding the transmission of the H5N1 virus among mammals is not just a scientific milestone; it's a direct warning."
Araya also stated that "the fact that this virus, historically associated with birds, has managed to adapt to marine mammals on our coasts, and that there is already at least one serious human case associated with it, forces us to rethink the boundaries between animal, environmental, and human health."
"Today we're talking about a panzootic, an animal pandemic, but what's at stake goes beyond that; public health is at risk," he insisted.
Emphasizing this, the expert argued that "Chile faces the challenge of urgently integrating a One Health approach that considers the close relationship between ecosystems, animals, and people. The mass death of wildlife, coupled with potential contagion from domestic animals or contaminated food, presents us with a scenario we cannot ignore."
"This isn't about alarmism, but about anticipation. Without robust epidemiological surveillance, health education, and integrated policies, the next outbreak won't be a surprise, it will be a consequence," he concluded.
EFFECTS IN THE REGION
Regarding the current situation regarding avian influenza, Jorge Fernández, Regional Director of the Agricultural and Livestock Service (SAG), stated that "since April 2024, the Coquimbo region has been declared free of avian influenza, with the last positive case detected on July 20, 2023. Since then, we have not recorded any new outbreaks in the area."
For his part, the Regional Director of the National Service for Disaster Prevention and Response (SENAPRED) of Coquimbo, Angelo Hernández revealed that during 2023, in the region the following died from avian flu: 1,420 Humboldt penguins; 2,240 specimens of common sea lion; 128 Magellanic penguins; 20 Chungungos; 14 Southern sea lions; 10 Juan Fernández fur seals; 9 Porpoises; 1 Common dolphin and others (13).
It should be added that between 2023 and 2024, an isolated case was confirmed in a person in a region in the north of the country.
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