Highly pathogenic avian influenza (H5N1) has been discovered spreading among US dairy cows, causing alarm among researchers worldwide. The lack of transparency in the federal investigation into the outbreak has raised concerns among experts, who are worried about the potential impact of this fast-spreading virus.
The US Department of Agriculture (USDA) has reported 32 affected herds in eight states, with unclear links between cases. Researchers are still unsure of how the virus is spreading among the cows, with some speculating that contaminated milk equipment may be a possible vector.
In a troubling development, the virus was found in a North Carolina herd with no visible symptoms, sparking fears of silent spread in other asymptomatic herds. The USDA is now encouraging testing for H5N1 in herds showing clinical symptoms and is reimbursing for testing asymptomatic cows.
There are concerns about the virus evolving to infect mammals, with the potential risk of spillover to humans. Critics have accused the USDA of not sharing enough genetic data from the investigation, but the agency has recently announced the release of 239 genetic sequences to the Global Initiative on Sharing All Influenza Data (GISAID), adding raw data to the US federal database.
Despite reassurances from the USDA and the Centers for Disease Control and Prevention (CDC) that the risk to the public is low, precautions for farmworkers and those who have direct contact with animals are advised. Fortunately, H5N1 in cows is relatively mild and has not caused any deaths, as infected milk is destroyed before entering the milk supply.
The Food and Drug Administration (FDA) remains confident in the pasteurization process’s ability to kill the virus in milk, although some experts are requesting data confirmation. As the investigation into the outbreak continues, researchers are working to understand the implications of this new strain of avian influenza on both animal and human health.
