2024-09-24 15:28:07
A review directed Instituto Pirbright on the sustained transmission of avian influenza between mammals of different species concluded that international control strategies had failed.
Published in the magazine ‘Creation‘, the study analyzed outbreaks in mink farms in Europe, marine mammals in South America and livestock in the United States, raising questions about the possibility that humans could be affected next.
The study, led by a zoonotic influenza expert Thomas Peacockexamined how recent changes in the ecology and molecular evolution of the H5N1 virus in wild and domestic birds have increased opportunities for spread to mammals. In addition, possible evolutionary pathways that could turn the current global panzootic H5N1 into a human pandemic are explored.
“Influenza A virus (IAV) has caused more documented global epidemics in human history than any other pathogen. “Historically, pigs have been considered the best intermediates for avian viruses to adapt to animals before jumping to humans,” Peacock explained. “However, H5N1’s change in ecology has opened the door to new evolutionary pathways».
The review also highlighted gaps in control strategies, such as a reluctance to use modern vaccination and surveillance technologies, as well as a lack of data collection on H5N1 transmission between cows and humans on US dairy farms.
According to the authors, while previous generations of US livestock producers eradicated FMD by quickly sharing epidemiological information, the lack of information currently leaves researchers, veterinarians and policymakers without a clear picture. of the situation.
The article also notes that current practices for H5N1 detection focus wild animals on dead animals, leaving room for virus variants to spread latently in live animals.
Moving in silence
“What worries scientists is the possibility of undetected viruses circulating silently among agricultural workers, pig farms or developing countries, undetected due to limited testing requirements , fear of the authorities or lack of resources”.
The evolutionary process of «rgenomic arrangement“, in which viruses with genomes that are divided into exchange segments during replication in a host, are currently driving global panzootics. The association between H5N8 and low pathogenicity viruses (LPAI) that originated the H5N1 virus in the United States is believed to have occurred in Europe or Central Asia around 2020, affecting South American marine mammals and cattle. American pet.
Although chickenpox vaccines reduce the risk of disease, they do not prevent infection, and their effectiveness varies.
The authors consider the possibility that H5N1 remains in Europe and the United States as a turning point for pathogenic avian influenza (HPAI). “New control strategies are needed, including vaccines. “Although chicken vaccines have reduced the disease burden, they do not prevent infection and their effectiveness varies.”
The authors also mention that, if H5N1 begins to spread in humans, vaccines based on mRNA technology, which are already antigenically related to circulating viruses, can be produced on a large scale.
Like it the severity of a possible future H5N1 pandemic is unclear. Recent human infections have a much lower death rate than previous outbreaks in Asia, where half of those infected died. This may be because recent cases in the US have been caused by eye infections, rather than viral pneumonia in the lungs.
Finally, we note that adults may have some immunity to H5N1 due to childhood exposure, while people born after the H3N2 pandemic in 1968 may be more vulnerable to severe illness in the event of H5N1.
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