The sheer scale of the U.S. bird flu outbreak is hard to fathom.
More than 100 million farmed birds have been infected with H5N1 since 2022, followed by roughly 170 herds of dairy cows, along with virus detections in more than 200 other mammals — humans included. Recently, a handful of farm workers in Colorado were infected, marking the country's first human outbreak: Six confirmed cases are linked to culling efforts at one poultry farm, and at least one likely case is tied to culls at another nearby facility. And while the spread may have been chicken-to-human, the virus strain is similar to the form of bird flu tearing through dairy farms across more than a dozen states.
The country's total human infection tally, of less than a dozen confirmed cases since 2022, pales in comparison to the staggering case counts among poultry and livestock. There haven't been any farm worker deaths, and no cases linked to dairy farms have popped up yet in Canada, either. Yet this new, unusual cluster of human H5N1 cases may be a harbinger of looming challenges to come, all while the broader U.
S. outbreak could be surging out of control. 2 more poultry workers in Colorado infected with H5N1 bird flu: CDC How H5N1 avian flu went global — and what scientists are bracing for next The timing is far from ideal, several scientists told CBC News, with farm worker infections ticking up mere months before the return of the usual flu season, and the fall migration of millions of wild birds — givin.