Milking practices linked to Bovine H5N1 transmission

By Scout Nelson

A Kansas State University study has uncovered that milking practices may significantly contribute to the spread of the bovine H5N1 influenza virus in dairy cattle, highlighting the need for improved sanitary procedures.

Researchers at Kansas State University have recently published groundbreaking findings that link certain milking practices to the transmission of the bovine H5N1 influenza virus, which has been affecting dairy cattle across the United States.

The study, led by Juergen Richt, a distinguished professor in diagnostic medicine and pathobiology, was released in the prestigious journal Nature.

The research focused on the H5N1 clade 2.3.4.4b virus, a strain identified in U.S. cattle in spring 2024, and a comparative strain, H5N1 euDG, circulating in Europe. Experimentally infected calves and lactating cows provided critical data on how the virus spreads within a farm setting.

While the calves showed only mild symptoms and moderate viral replication without further transmission, the infected dairy cows exhibited severe symptoms of mastitis and a significant drop in milk production, accompanied by high viral loads in their milk.

These findings suggest that the virus may spread primarily through milking processes rather than through respiratory droplets, as was previously suspected. This revelation points to milking equipment and procedures as probable vectors for the virus, underscoring the urgent need for stringent biosecurity measures in milking practices to prevent further spread of the disease.

The implications of these results are significant, given the U.S. has nearly 10 million dairy cows, and the dairy industry is a crucial component of the agricultural sector. The potential economic repercussions of an uncontrolled outbreak could be devastating, not only for farmers but also for the broader economy.

Additionally, the risk to human health cannot be overlooked, as interactions with infected animals or contaminated products pose a potential zoonotic threat.

The study, funded by the State of Kansas National Bio and Agro-Defense Facility Transition Fund, was conducted at K-State's Biosecurity Research Institute and in collaboration with Germany's Friedrich-Loeffler-Institute.

This research not only highlights the need for improved sanitary practices in the dairy industry but also sets a foundation for future guidelines to mitigate the risks associated with bovine H5N1 influenza.

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