Health organizations in the United States initiate investigations into H5N1 avian flu's impact on dairy employees and dairy goods.
Federal health and food agencies in the US are stepping up research to address a recent outbreak of H5N1 bird flu that has infected dairy cattle and potentially spread to workers in the industry.
The Centers for Disease Control and Prevention (CDC) is teaming up with Michigan to examine if workers exposed to infected cows have also been infected. Meanwhile, the Food and Drug Administration (FDA) is testing flash pasteurization methods to ensure they effectively neutralize all virus in milk.
These projects are part of a larger research initiative announced by federal agencies on Tuesday, aiming to understand the transmission dynamics of the bird flu strain that jumped from birds to dairy cattle at the beginning of the year. Since late March, more than 120 herds across 12 states have tested positive for the contagious infection, according to the US Department of Agriculture (USDA).
Dr. Eric Deeble, acting senior adviser for highly pathogenic avian influenza at the USDA, stated that the infection is primarily spread through contact with raw milk. Initially, the movement of cattle was the primary cause of the infection's spread. However, since the USDA ordered cattle testing before interstate movement in late April, the infection has been transmitted between farms through shared equipment and workers.
A recent study by the Michigan Department of Agriculture and Rural Development (MDARD) found that milk has high viral loads, making it a high-risk factor for transmission. Though the exact method of human transmission isn't clear, MDARD Director Dr. Tim Boring speculates it may not be solely dependent on whether the virus is on or in people.
Dairy farmers have been hesitant to allow government officials onto their farms for widespread testing of their herds, and farmworkers have been reluctant to test due to potential missed work and pay. In an effort to encourage participation, Michigan announced last week that it would offer up to 20 dairy farms a maximum of $28,000 each to participate in research.
In response, the CDC partnered with the Michigan Department of Health and Human Services to conduct a study testing the blood of farm workers for antibodies to the H5N1 virus. The goal is to determine if workers who have been exposed to infected cows are experiencing asymptomatic infections.
Additionally, the FDA has started another round of dairy product sampling to address gaps in its previous testing. This time, products like raw milk cheeses, cream cheese, ice cream, and butter will be collected from store shelves.
Initial FDA testing of various dairy products revealed traces of the virus in 1 out of 5 items sampled earlier this year. However, further testing found that these viral fragments were inactive and could not make anyone sick, leading the agency to declare milk and other dairy products safe to consume if they're pasteurized.
Recent lab studies published in the New England Journal of Medicine, however, have raised concerns about the effectiveness of flash pasteurization in completely neutralizing all virus in milk. The FDA plans to conduct further research to address these concerns. Other studies on the FDA's to-do list include measuring the persistence of the virus in cheese as it ages and pooled testing of raw milk samples from dairies.
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The Centers for Disease Control and Prevention (CDC) is collaborating with Michigan to evaluate if dairy workers exposed to infected cows have also contracted the illness. Furthermore, the Food and Drug Administration (FDA) is studying the efficiency of enhanced pasteurization methods in eliminating the H5N1 virus from milk.
