A second poultry farm in Colorado has reported a bird flu case in a worker, making it the state’s seventh human case this month. The outbreak has mainly affected dairy cows, and the latest case is a presumptive positive, meaning it tested positive at the state level but is waiting for confirmation from the CDC. The worker was from a poultry facility in Weld County, where six other poultry workers also recently tested positive for bird flu.
In late March, the US Department of Agriculture confirmed that the H5N1 bird flu, which had been spreading among wild birds, had jumped to dairy cows in the US. This spread has affected at least 168 herds in 13 states and resulted in 11 human cases, four of which were dairy workers and seven poultry workers. The seven human cases among poultry workers have all been in Colorado, highlighting a significant concern for the state’s poultry industry.
Second Colorado Poultry Worker Tests Positive for Bird Flu Amid State’s Ongoing Outbreak
The recent increase in human infections among Colorado poultry workers is notable, given the ongoing H5N1 outbreak that has impacted poultry farms across the US since January 2022. With over 1,000 outbreaks in 48 states, the virus primarily spread from wild birds to poultry. The new surge in cases among poultry workers only began after the virus spread to dairy cows, indicating a complex transmission path that now includes humans.
Genetic testing has not identified significant changes in the virus to explain the recent increase in human cases. There is no evidence of human-to-human transmission, and the CDC continues to assess the risk to the general public as low. All human cases so far have been mild and responsive to antiviral treatments. Federal officials have suggested that extreme summer heat may be contributing to the uptick in human cases, as high temperatures and industrial fans make it difficult for poultry workers to maintain proper protective equipment.
The precise mechanism of how the virus is spreading from dairy farms to poultry farms remains unclear. However, Colorado’s significant role in the outbreak is apparent, as the state has the highest number of infected herds, with Weld County being particularly affected. This spillover from dairy to poultry farms in Colorado underscores the need for ongoing vigilance and effective biosecurity measures to control the spread of H5N1.
