The CDC finds itself not only trying to blunt the spread of the H5N1 virus, but also playing catch-up with testing methods that have been largely resisted among America’s farmers. Can new interventions can ward off mass human-to-human transmission of this strain? Via Fortune:

“We will have a bird flu pandemic,” Robert Redfield, former director of the CDC, bluntly predicted in a television interview in June. “It’s not a question of if; it’s more a question of when … Once the virus gains the ability to attach to the human receptor and then go human to human, that’s when you’re going to have the pandemic.”

A CDC study released Thursday did little to alleviate that concern. The report found that a significant percentage of H5N1 infections went undetected in dairy workers who worked on farms with cows that were confirmed positive for the virus last summer. Among 115 farm workers who underwent blood tests in Michigan and Colorado, eight had evidence of recent infection in the form of antibodies—but only half of them could recall having symptoms. “All eight had either been milking cows or cleaning the milking mechanisms, officials said.

Among other things, that result suggests that many more American farm workers could become or already have been infected with the virus without knowing it—all the more reason, the experts say, for federal and state health agencies to aggressively offer testing and enhanced personal protective equipment(PPE) to those with boots on the ground at U.S. dairy and poultry farms.

“This generally confirms what we knew: There are more people that are getting infected on farms than the official tally. The serology bears that out,” says Amesh Adalja, senior scholar at the Johns Hopkins University Center for Health Security. “That’s the reason why so many of us have been wanting more aggressive serological testing on farms, in order to understand the extent of infection and better understand the risks that the virus poses (there).”

Here we go again.