As the world continues to grapple with the effects of COVID-19, a small but concerning virus has also started to make headlines: the H5N8 bird flu strain, which killed five swans, three seals, and a fox at an unnamed U.K. wildlife rehabilitation center in late 2020, according to a recent report.
The same virus also infected poultry workers in Russia in February of 2021. H5N8 is one of a few rare strains—including H5N1, H7N9 and H5N6—that can make the leap from birds to people.
The outbreak at the U.K. facility began when five infected swans were brought in for rehabilitation in October and November of 2020. The birds appeared to be doing well until they rapidly became weak and died between November 25-29, 2020.
The swans were isolated in a quarantine unit, as all newly arrived animals are, but the seals and fox were housed in the same unit in separate cubicles, and approximately a week later, they too became sick and died. The seals developed seizures, and the fox exhibited signs of weakness and loss of appetite.
The mode of transmission from the swans to the other animals indicates that H5N8 is spread through aerosols or infected surfaces, just as COVID-19 is.
In general, such spillover infections from birds to mammals are unusual, making the outbreak at the U.K. wildlife center all the more noteworthy. “Although genetic analyses indicated no increased risk for human infection with the H5N8 viruses in this outbreak, the investigation shows how these viruses may have unexpected and severe health risks for mammalian species,” the authors of the report wrote. “However, such spillover disease events in atypical host species constitute additional factors for veterinary authorities to consider during disease outbreaks and highlight the importance of wildlife disease surveillance that uses interdisciplinary and collaborative approaches.”