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Source: https://www.science.org/content/arti...h-america-stay
‘We’re nervous.’ Deadly bird flu may be in North America to stay
H5N1 has continued to kill wild birds and poultry this summer. The fall migration could bring it back in force
23 Aug 20224:30 PMByErik Stokstad
When an outbreak of highly pathogenic H5N1 avian influenza spread across North America this spring, researchers hoped for a replay of what happened after a different avian flu variant arrived in the United States in December 2014. Although more than 50 million birds died or were destroyed in a matter of months, costing farmers more than $1.6 billion, the virus had essentially vanished by June 2015. Poultry outbreaks ended, wild birds stopped dying, and migratory waterfowl didn’t bring the virus back when they returned from their summer breeding grounds in Canada.
But this time is different. H5N1 infections in both wild bird species and poultry have continued in parts of the United States and Canada over the summer, dashing hopes that warmer temperatures would halt the spread. And whereas the 2015 outbreak primarily affected Midwest poultry farms, H5N1 has spread to practically the entire continental United States and infected at least 99 wild bird species, a record. Whether migratory birds will cause additional introductions in the fall is “the million-dollar question,” says Bryan Richards, emerging disease coordinator at the U.S. Geological Survey’s National Wildlife Health Center.
Even if they don’t, scientists worry the virus may continue to circulate year-round, posing a permanent threat to poultry farming and wild birds, including several endangered species. “Impacts on wild birds may persist for a very, very long time,” Richards says. Europe may show what lies ahead: There H5N1 has already become a fixture in wild birds and has caused bigger and bigger outbreaks over the past 3 years, causing record damages to the poultry industry...
‘We’re nervous.’ Deadly bird flu may be in North America to stay
H5N1 has continued to kill wild birds and poultry this summer. The fall migration could bring it back in force
23 Aug 20224:30 PMByErik Stokstad
When an outbreak of highly pathogenic H5N1 avian influenza spread across North America this spring, researchers hoped for a replay of what happened after a different avian flu variant arrived in the United States in December 2014. Although more than 50 million birds died or were destroyed in a matter of months, costing farmers more than $1.6 billion, the virus had essentially vanished by June 2015. Poultry outbreaks ended, wild birds stopped dying, and migratory waterfowl didn’t bring the virus back when they returned from their summer breeding grounds in Canada.
But this time is different. H5N1 infections in both wild bird species and poultry have continued in parts of the United States and Canada over the summer, dashing hopes that warmer temperatures would halt the spread. And whereas the 2015 outbreak primarily affected Midwest poultry farms, H5N1 has spread to practically the entire continental United States and infected at least 99 wild bird species, a record. Whether migratory birds will cause additional introductions in the fall is “the million-dollar question,” says Bryan Richards, emerging disease coordinator at the U.S. Geological Survey’s National Wildlife Health Center.
Even if they don’t, scientists worry the virus may continue to circulate year-round, posing a permanent threat to poultry farming and wild birds, including several endangered species. “Impacts on wild birds may persist for a very, very long time,” Richards says. Europe may show what lies ahead: There H5N1 has already become a fixture in wild birds and has caused bigger and bigger outbreaks over the past 3 years, causing record damages to the poultry industry...