Główne pojęcia
Avian influenza viruses pose a significant pandemic risk, as they could potentially acquire the ability to spread efficiently among humans, leading to large-scale transmission due to lack of immunity.
Streszczenie
The content discusses the assessment by European scientists regarding the pandemic risk posed by avian influenza viruses. Key points:
- Avian influenza A(H5N1) viruses continue to spread among wild bird populations in the European Union (EU), and there is a threat of new strains carrying potential mutations for mammalian adaptation entering the EU and the wider European Economic Area (EEA).
- If the avian A(H5N1) influenza viruses acquire the ability to spread efficiently among humans, large-scale transmission could occur due to the lack of immune defenses against H5 viruses in humans.
- Despite many occurrences of human exposure to avian influenza since 2020, no symptomatic or productive infection in a human has been identified in the EU/EEA. The virus has not yet acquired the mutations required for airborne transmissibility between humans.
- However, it remains difficult to predict the evolutionary direction the virus will take in the future, and the "clock resets every minute" as the virus has the potential to spill over from birds to humans.
- The European report recommends a range of cautionary measures, including enhanced surveillance, access to rapid diagnostics, sharing of genetic sequence data, and a One Health approach to limit the exposure of mammals, including humans, to avian influenza viruses.
- The report also calls for consideration of preventative measures, such as vaccination of poultry flocks.
- Overall, the report is designed to move zoonotic infectious diseases higher up the agenda, as they should have been before the COVID-19 pandemic.
Statystyki
No symptomatic or productive infection in a human has been identified in the EU/EEA.
After almost three decades of human exposure to the A(H5N1) virus of the Gs/GD lineage, the virus has not yet acquired the mutations required for airborne transmissibility between humans.
Cytaty
"If avian A(H5N1) influenza viruses acquire the ability to spread efficiently among humans, large-scale transmission could occur due to the lack of immune defenses against H5 viruses in humans."
"Clearly, humans are being exposed in the current USA cattle outbreak. But, arguably, what is more significant is how few cases there have been with this virus lineage and its close relatives, despite massive global exposures over the last 3 years. All diagnosed human cases seem to have been singletons, with no evidence of human-to-human transmission."
"The trouble is, the clock resets every minute. Every time the virus has come out of a bird and gone somewhere, the clock is reset. So you can never say that just because it hasn't happened since whenever, it's never going to happen."