About 7% of dairy workers exposed to the avian flu that is spreading through U.S. herds have become infected themselves, federal experts estimate.
That number highlights concerns that circulating strains of bird flu might become highly infectious in humans, according to a new report from the U.S. Centers for Disease Control and Prevention.
"The findings support the need for active monitoring of exposed workers and testing to detect and treat [ avian flu ] infections, including those in persons with very mild symptoms," concluded the research team led by Alexandra Mellis, a CDC health scientist. "These efforts should be coupled with farm worker education about infection risks and prevention measures." The H5 bird flu is widespread in wild birds and is causing outbreaks in U.
S. poultry and dairy farms , the CDC says. There have been outbreaks in 443 U.
S. dairy herds, and 48 states have reported outbreaks in poultry. While the public health risk is still low, the CDC is watching the situation closely for any signs that the flu might mutate into a form that is more contagious to humans.
There have been a total of 46 confirmed human cases of bird flu in the United States. For the study, CDC officials tracked the health of 115 dairy workers in Michigan and Colorado who handled herds that were experiencing a bird flu outbreak. Blood tests revealed that 7% of the workers carried antibodies to the bird flu, indicating that they had been infected at some point, according to results pub.