Growing Concerns Over Avian Influenza's Spread to Humans and Other Species

Growing Concerns Over Avian Influenza's Spread to Humans and Other Species
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Thursday 18 April 2024, 19:08 - Last updated: 19 April, 08:19
Concern continues to grow worldwide over the spread of avian influenza, amid fears that it could become a concrete threat to humans as well. The latest alert comes from the World Health Organization (WHO), which today expressed "enormous concern" over the increasing spread of the H5N1 strain of avian influenza to new species, including humans. "It remains, I think, a great concern," said Jeremy Farrar, head of the United Nations health agency, at a press conference in Geneva. Avian influenza, alert in New York. Appeal to citizens: "Do not touch birds or sick animals." The fear, he explained, is that the H5N1 virus, which in people infected through contact with infected animals has shown "an extraordinarily high mortality rate," will adapt to become capable of transmission from human to human. Currently, there is no evidence of human-to-human transmission of the H5N1 virus. Between 2003 and April 1, 2024, WHO has reported a total of 889 human cases of avian influenza in 23 countries, including 463 deaths, bringing the mortality rate to 52%. At the beginning of April, American authorities reported that a person had tested positive for avian influenza after being infected by a dairy cow in Texas. Currently, cases of transmission to humans are very rare. A nine-year-old child, carrying the H5N1 strain, died of avian influenza in Cambodia in February, after three deaths in the same country in 2023. In the United States, the patient showed "eye redness (corresponding to conjunctivitis) as the only symptom," authorities said, adding that he was isolated and treated with an antiviral drug used for influenza. "When it enters the mammalian population, then it gets closer to humans," Farrar said again, warning that "this virus is just looking for new hosts. It's a real concern." Farrar then called for strengthening monitoring, warning that it is "very important to understand how many human infections are occurring, because that's where the virus will adapt." He also stated that efforts are underway to develop vaccines and therapies for H5N1 and emphasized the need to ensure that regional and national health authorities around the world have the ability to diagnose the virus, so that "if H5N1 were to reach humans, with transmission from human to human, the world would be able to respond immediately," he concluded, urging equitable access to vaccines, therapies, and diagnostics. In a recent report, the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) also expressed strong concern: "If avian influenza A/H5N1 viruses acquired the ability to spread among humans, large-scale transmission could occur." In the midst of the pandemic, in 2020, a new variant of the A/H5N1 virus (named appeared and quickly became dominant. Since then, the "number of infections and transmission events among different animal species" has increased, the report reads. These continuous passages between animals and different species increase the chances for the virus to mutate or acquire portions of other viruses that make it more suited to infect mammals. In reality, A/H5N1 has already taken steps in this direction. It has learned to multiply more effectively in mammalian cells and to evade some components of the immune response. This has already allowed it in recent years to strike a wide range of wild mammals and also pets, such as cats. Lastly, the case of the infected cow in the USA. In Italy, 11 new outbreaks of highly pathogenic avian influenza of subtype H5N1 have been confirmed in poultry farms between the end of March 2023 and December 2023. So far in 2024, only one outbreak has been confirmed in February.
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