Outbreaks of highly pathogenic avian H5 influenza viruses are now originating outside of Asia, suggesting a shift in the global distribution of the viruses.
This is the conclusion of an international team of researchers who argue that the “epicenter” of these diseases has now expanded to include parts of Africa and Europe.
At present, thankfully, bird flu strains like H5N1 do not infect humans easily. In fact, fewer than 900 cases have been known since 1997.
However, in the rare cases that they do, they can have mortality rates as high as 50 percent.
H5N1 activity has intensified since 2021, infecting and killing increasing numbers of wild birds and poultry, as well as posing a risk to mammals, including us humans.
For all the latest on news, politics, sports, and showbiz from the USA, go to Daily Express US
The research was undertaken by virologist Professor Vijaykrishna Dhanasekaran of the University of Hong Kong and his colleagues.
To investigate the changing origins and trends in highly pathogenic avian H5 outbreaks, the team studied data collected by both the United Nation’s Food and Agricultural Organization and the World Organization for Animal Health between the years 2005 and 2022.
They also analyzed more than 10,000 whole viral genomes.
The team identified key bird flu resurgence events in 2016/2017, for which genome analysis indicated that the viral lineages originated within Asia — specifically, from China.
In contrast, the researchers found that two more recent H5 viruses — which were identified between 2020 and 2022 — were found to have emerged from bird populations in Africa and Europe.
Genomic analysis concluded that these strains evolved by mixing genetic material with other, low pathogenic viral variants as they spread.
The team wrote: “These results highlight a shift in the HPAI H5 epicenter beyond Asia and indicate that increasing persistence of HPAI H5 in wild birds is facilitating geographic and host range expansion.”
This, they added, can also increase the speed with which the viruses spread, as well as the rate at which they mix and evolve.
The researchers concluded: “Elimination strategies in domestic birds therefore remain a high priority to limit future epizootics.”
The full findings of the study were published in the journal Nature.
