Key takeaways:

• The USDA has confirmed detection of a new bird flu strain (D1.1) in dairy cattle, previously unseen in cows.
• 90% of bird flu infections in dairy cattle this year were from the original strain (B3.13), prior to this discovery.
• The new strain is linked to respiratory symptoms in affected cattle and was identified through a national milk testing strategy.

The U.S. Department of Agriculture (USDA) confirmed on February 5 that a second strain of bird flu, classified as D1.1, has been found in U.S. dairy cattle for the first time. This recent detection presents a significant concern as it follows a year marked by widespread bird flu infections among dairy herds across the nation. Prior to this, all reported infections among dairy cows had been attributed to the B3.13 strain.

The discovery was announced following genome sequencing of milk samples in Nevada, where the new strain was first identified. This strain had been the predominant variant among wild birds this past fall and winter, indicating a possible spillover from avian sources to cattle. According to the ABC News, there have been almost 70 human cases of bird flu reported in the U.S. since April, most of whom worked in agricultural settings.

The respiratory symptoms reported in infected cattle, including coughing and sneezing, have led to concerns about animal health and production. In a statement from the Nevada Department of Agriculture, it was noted that at least four herds have tested positive for this new strain, prompting quarantine measures in several counties. Experts like Gail Hansen, a veterinary and public health consultant, stress the importance of early intervention to prevent wider spread, particularly to other states. 'We want to avoid the same scenario that happened last year when infected cattle were shipped across state lines,' Hansen stated.

The implications of the D1.1 strain are serious, especially considering it was linked to a fatal human case in Louisiana and has caused more severe symptoms compared to the previously dominant strain. As Virginia’s Chief Veterinarian Beth Thompson remarked, “It’s modifying itself so it's not just staying in poultry and wild waterfowl. It’s picking up a home in mammals.” These developments emphasize the urgent need for enhanced biosecurity measures on farms to mitigate the risk of further outbreaks.

While the situation remains concerning, officials maintain that the risk to the general public is low, and they continue to investigate the situation. A representative from the USDA confirmed that the agency is actively collaborating with state officials to monitor the outbreak and gather more epidemiological information detailed in the Reuters report.

As the situation unfolds, the USDA remains committed to its eradication strategy, although experts warn this new strain’s emergence could complicate existing efforts. Monitoring of dairy herds will continue, with increased testing being a priority to assess the impact and spread of the D1.1 strain in U.S. agriculture.

For more detailed information, visit CBS News and Forbes.