The highly pathogenic avian influenza — or bird flu — sweeping across the globe has killed more than 12,000 wild birds in Colorado and the virus is jumping into mammal populations as well, state wildlife officials say.
And it’s unclear when the spread might relent.
“This is unprecedented,” Kristy Pabilonia, director of clinical diagnostics for Colorado State University’s College of Veterinary Medicine and Biological Sciences, said. “The fact that it’s now so distributed with our wild bird populations, there are a lot of questions about the best next steps.”
That death toll is likely a “significant underestimate” of the true number of Colorado’s wild birds killed by the virus, Travis Duncan, spokesman for Colorado Parks and Wildlife, said.
The number of birds in commercial flocks — largely chickens and turkeys — killed by the virus is far higher, which has led, in part, to an egg shortage and price increase across the country.
State officials tracked large-scale “die-offs” of more than a thousand geese twice in northeast Colorado, Duncan said. Once at the Jumbo Reservoir and then at the Prewitt Reservoir. Additional, smaller die-offs were tracked at most of the reservoirs near Lamar, he added.
Data collected by the U.S. Department of Agriculture shows cases of bird flu in at least 30 of Colorado’s 64 counties. Among the birds killed are Canada and Snow geese, great horned owls, red-tailed hawks and five bald eagles.
In Denver, the virus claimed two Chilean flamingos (classified as captive wild birds), a swan goose and a scaly-sided merganser, among a slate of geese, ducks and owls, the data shows.
Domestic flocks have been hard hit (with nearly 6.3 million birds affected in commercial operations, USDA data shows) but at least humans have the ability to quarantine those flocks and control the spread of the disease, Pabilonia said. In the wild, officials have little or no control.
The virus spreads easily among certain species of geese as well as the raptors that feed on infected birds, Pabilonia said.
As bird flu spreads throughout wild creatures it also evolves, Pabilonia said. The virus is decades old and it’s changed repeatedly throughout the years. Certain variants jump into species of mammals.
In Colorado a mountain lion, black bear and skunk have all been confirmed to have contracted the virus. Duncan said wildlife officials are testing many more animals for the virus, though he couldn’t say how many test results remain outstanding.
“The lab has a pretty steady stream of animals coming through necropsy as well as swabs or other samples collected by the field,” Duncan said. “This number would change on a daily basis.”
Dogs and cats could be susceptible to the virus, Pabilonia said. Particularly in the Front Range, which has a higher concentration of people and pets than rural Colorado. But so far there haven’t been any reports of dogs or cats contracting the virus, she said.
Pet owners should be aware of the risk, but Pabilonia doesn’t recommend any major lifestyle changes. People who own dogs and cats should already avoid letting their pets interact with wildlife in general and the bird flu outbreak underscores the importance of that rule, she said.
Similarly, humans can also catch the virus but that’s relatively uncommon and unlikely, Pabilonia said.
“But that doesn’t mean we shouldn’t pay attention to it,” she added. “Generally we never want an unchecked organism to be spreading through animal populations.”
