Recent developments in the United States have seen health agencies initiating fresh rounds of testing on dairy workers and milk products to gain a deeper understanding of the potential impact of H5N1 bird flu.
The US Centers for Disease Control and Prevention (CDC) have joined forces with the state of Michigan to commence a crucial study aimed at evaluating whether individuals exposed to infected cattle have contracted the virus. Concurrently, the US Food and Drug Administration (FDA) is investigating the efficacy of flash pasteurization in neutralizing any infectious virus present in milk, following concerns raised by recent studies.
The emergence of H5N1 bird flu in dairy cattle earlier this year has led to over 120 herds across 12 states testing positive for the highly contagious infection. The US Department of Agriculture confirmed that the virus appears to be spreading through contact with raw milk.
Dr. Eric Deeble, acting senior adviser for highly pathogenic avian influenza at the USDA, highlighted the transmission of the virus through milk. Early on, the movement of cattle primarily facilitated the spread of the infection. However, since mandatory testing of cattle before interstate movement was implemented in late April, the virus has been disseminated between farms via shared equipment and workers.
Dr. Tim Boring, Director of the Michigan Department of Agriculture and Rural Development (MDARD), emphasized the high viral loads present in milk, posing a significant transmission risk. The exact mechanism by which the virus utilizes humans for transmission remains unclear.
Efforts to conduct widespread testing on dairy farms have faced resistance from farmers and workers, with concerns about potential work disruptions and loss of income. To incentivize participation in research, Michigan announced financial assistance for dairy farms, with the CDC and FDA launching studies to assess asymptomatic infections among farm workers and address gaps in dairy product testing, respectively.
The FDA's recent testing of dairy products revealed traces of the virus in a portion of samples, although subsequent analysis confirmed the viral fragments were inactive and posed no health risk when products were pasteurized. However, recent studies have raised questions about the effectiveness of flash pasteurization in completely neutralizing the virus in milk, prompting further research.
Ongoing investigations by the FDA include assessing the virus's persistence in aging cheese and conducting pooled testing of raw milk samples from dairies. While specific timelines for results were not provided, the FDA aims to deliver findings in the near future.
