The current strain of the avian influenza, which has been decimating bird populations globally, is perilously different than previous disease outbreaks, according to US researchers who are calling for urgent action.
A new study led by a team from the University of Maryland found that the current strain of the disease that is killing millions of birds is “different” from previous decades, with birds dying in unprecedented numbers.
“We’ve been dealing with low pathogenic avian influenza for decades in the poultry industry, but this is different,” said Jennifer Mullinax, co-author of the study and an assistant professor in at the University of Maryland’s department of environmental science and technology.
“This high pathogenic virus is wiping out everything in numbers that we’ve never seen before,” said Mullinax.
The study, published in Conservation Biology, was conducted by tracking the arrival and progression of the lethal avian flu outbreak in North America to see how the latest upsurge of the disease compares to previous ones.
Researchers analyzed five different data sources that had information on the presence of avian flu among wild birds and poultry in the US and Canada as well as a global database that had information from 2014 until 2023.
Unlike the 2015 outbreak of avian flu (H5N8), the outbreak seen in late 2021 (H5N1) has caused mass mortality for wild birds, which makes the highly pathogenic virus more difficult to wipe out. “Unlike H5N8, this disease is heavily impacting wild birds,” said Johanna Harvey, lead author of the study and a postdoctoral researcher at the University of Maryland.
“It’s difficult to estimate how many birds are truly affected across wild populations, but we’re seeing dramatic disease impacts in raptors, sea birds and colonial nesting birds. And we now have the highest amount of poultry loss to avian influenza, so this is a worst-case scenario.”
Some 58 million domestic poultry were infected or were killed to stop the spread of infection in the US, as well as 7 million in Canada, researchers found.
The latest outbreak of avian flu may have also shifted to a year-round disease from a more seasonal disease in previous outbreaks.
The 2015 avian flu outbreak generally happened in the fall, when farmers could prepare and have more time to recover from losses. But the latest outbreak is occurring throughout the year, in the summertime for wild birds and during the spring and fall for domestic poultry.
Researchers concluded that the deadly impact of the disease on wild birds and the change from seasonal infections to ones occurring year-round could signal a dangerous change in the avian flu in the US.
The team also concluded that the avian flu will probably become endemic, which could affect food security and the economy.
The study called for coordination between national and regional leaders to manage the spread of the disease. “This paper illustrates how unprecedented it is, and describes what we think is coming. It’s really a call to arms saying: we can’t afford to address this in our individual silos,” said Mullinax.
As of December, more than 140 million birds have died in the US, the UK and the EU from bird flu.
The strain has also been found in some mammals, including in bears in the US and wild dogs in a zoo in the UK, as well as a sporadic number of human cases.
In a report in March this year, the US Centers for Disease Control and Prevention said: “Since 2022, despite the wide geographic spread of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in wild birds and to poultry worldwide, with sporadic spillover to mammals, only a small number of sporadic human cases of A(H5N1) have been identified.
“All reported human cases since 2022 were associated with recent poultry exposures, and no cases of human-to-human transmission have been identified.”
The disease has increased the price of poultry and poultry products, including eggs, by 60% in the US in 2022.
