26 Sept 2024
Review of latest outbreaks led by The Pirbright Institute states “the severity of a future H5N1 pandemic remains unclear”.
Paul Imrie
Job TitleGlobal strategies to control highly pathogenic avian influenza (HPAI) outbreaks are “not working” and new ones are needed, scientists have warned.
A review of sustained mammal-to-mammal bird flu transmissions has raised questions about whether HPAI could establish in humans.
A paper in the journal Nature, led by zoonotic influenza specialist Thomas Peacock at The Pirbright Institute, studied the outbreaks of H5N1 that spread from Asia between 2020 and this year.
The paper states that in 2020, an H5N1 problem previously confined to Asian poultry spread globally, with a new genotype of viruses belonging to clade 2.3.4.4b.
It states: “Images of seal carcases decaying on Argentine beaches and yellow, curdled milk on H5N1-affected dairy farms show how the 2.3.4.4b H5N1 panzootic is different and previous control strategies are not working.”
On launch of the paper, Dr Peacock said: “Influenza A viruses (IAV) have caused more documented global pandemics in human history than any other pathogen.
“Historically, swine are considered optimal intermediary hosts that help avian influenza viruses adapt to mammals before jumping to humans.
“However, the altered ecology of H5N1 has opened the door to new evolutionary pathways.”
The paper states: “New control strategies are needed, including vaccination. Influenza vaccines are licensed for poultry that reduce disease burden, but do not prevent infection and have varying degrees of success.”
It also adds that “the severity of a future H5N1 pandemic remains unclear”, but does point out human infections have a lower case fatality rate compared to prior H5N1 outbreaks in Asia.
The review paper, funded through bodies including the UK’s Biotechnology and Biological Sciences Research Council, is available online now.
