2024-03-04 10:54:46
Avian Flu in Antarctica, the Lament of the Elephant Seals.
Southern Elephant seal relaxes
Bird flu, also known as avian influenza, is a viral disease that primarily affects birds, but in some cases it can be transmitted to humans. The virus responsible for bird flu belongs to the H5N1 subtype, although variants such as H5N6 and H5N8 have emerged. In rare cases, the infection can be transmitted from birds to humans, usually through direct contact with infected birds or their secretions.
The initial detection of the highly pathogenic H5N1 avian influenza virus in domestic waterfowl in southern China in 1996 marked the beginning of a series of events that have had a significant impact on human and animal health globally. Designated A/goose/Guangdong/1/1996, this virus soon gave rise to outbreaks in poultry in China and Hong Kong in 1997, with devastating consequences for the human population: 18 confirmed cases, of which six resulted in deaths. , with a mortality rate greater than 50%.
After a period of relative quiet in virus detection, the threat re-emerged in 2003, spreading across Asia with widespread outbreaks in poultry. By 2005, H5N1 had spread from wild birds to poultry in Africa, the Middle East and Europe, further expanding the global threat. This resurgence was characterized by genetic diversification of the virus hemagglutinin into several clades and genotypes.
Between 2014 and 2016, an evolution in the situation was observed with the appearance of new virus subtypes, specifically H5N6 and H5N8. Gene exchange between poultry and wild bird H5 viruses gave rise to these emerging subtypes. In this period, hemagglutinin continued to diversify, especially in clade 2.3.4.4, which spread across Asia, Africa, Europe, the Middle East, and North America. In turn, several genetic lineages and genotypes were identified, showing the complexity of the evolution of the virus.
Starting in 2018 and continuing through 2024, clade 2.3.4.4b viruses spread widely, marking a significant change in the epidemiology of avian influenza. The H5N6 and H5N8 subtypes became predominant globally, replacing the original H5N1 viruses. In 2022, more than 70 cases of human infections caused by the H5N6 virus were reported, along with 7 cases related to the H5N8 virus.
Transmission of bird flu to humans can occur in two main ways: directly from birds or contaminated environments, or through an intermediate host, such as pigs. Those exposed to potentially infected birds, such as workers in slaughter operations, or in close contact with potentially infected mammals, such as foxes or wild animals, should take appropriate precautions and be closely monitored after exposure.
Although it has been shown that avian flu can be transmitted through direct contact with birds or their contaminated environments, it has not been confirmed that the disease can be transmitted to humans through consumption of contaminated poultry products. Safe handling of raw meat and other ingredients, along with proper cooking and hygiene practices in the kitchen, are effective measures to prevent or reduce the risk associated with these potentially contaminated food products.
The spread of bird flu has reached alarming proportions in Antarctica, where hundreds of elephant seals have been found dead. There is justified fear that the highly contagious virus could cause one of the biggest ecological disasters of modern times if it reaches remote penguin populations. In this context, the death of at least one king penguin due to bird flu in Antarctica was recently reported.
Previous data from South Africa, Chile and Argentina have shown the susceptibility of penguins to the disease, with more than 500,000 seabirds dying in South America. Penguins, pelicans and boobies are among the most affected species.
Initial reports of the virus in Antarctica traced back to Bird Island, off South Georgia. Since then, mass deaths of elephant seals, as well as an increase in deaths of fur seals, gulls and brown skuas, have been recorded in other regions, including 1,500 kilometers west of South Georgia, among the southern fulmars of the Islands. Malvinas.
In Chile and Peru, the virus has wreaked havoc, with around 20,000 sea lions dead. The highly infectious H5N1 strain, which emerged in 2021, has led to the loss of millions of wild birds. The 2.3.4.4b strain has decimated bird populations in the UK, continental Europe, South Africa and the Americas, with seabird colonies experiencing losses of 50% to 60%. Although the H5N1 strain has not yet reached Oceania, the current situation poses a significant risk to the region’s ecosystems and wildlife.
In December 2023, avian flu was confirmed as the cause of the death of a polar bear in Alaska, signaling a potential threat to poorly controlled remote populations. Unique and vulnerable polar ecosystems face elevated risks from bird flu and climate change.
The evolution of avian flu from 1996 to 2024 reflects the complexity of the virus and its impact on human and animal health and global ecosystems. Effective management requires international efforts, addressing human and animal health, and considering the impact on biodiversity and polar ecosystems.
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