USDA Implements National Milk Testing Strategy to Try Halting Bird Flu Outbreaks in Dairy Herds

The U.S. Department of Agriculture is set to mandate bulk milk tank testing nationwide to address bird flu outbreaks in dairy herds.

As USA Today reports, in an announcement Friday, the US Department of Agriculture (USDA) said it issued a new federal order that milk samples be collected and shared with the federal agency for testing. Officials said this will facilitate comprehensive surveillance for H5N1, which has been circulating in U.S. dairy cattle since it was first detected in March. The USDA has previously stated the nation’s pasteurized milk supply is safe, with the heating process killing off dangerous pathogens. But public health officials have warned against drinking raw milk, which is not pasteurized and therefore might transmit the virus.

Over 700 dairy herds across the U.S. have tested positive for bird flu across 15 states, federal data shows. The majority, over 500 herds, have been in California, the nation’s largest dairy producing state.

The first round of testing under the USDA order is set to begin Dec. 16. “This new milk testing strategy will build on those steps to date and will provide a roadmap for states to protect the health of their dairy herds,” Agriculture Secretary Tom Vilsack said in a Friday statement. “Among many outcomes, this will give farmers and farmworkers better confidence in the safety of their animals and ability to protect themselves, and it will put us on a path to quickly controlling and stopping the virus’ spread nationwide.”

In addition to protecting the food supply, testing allows officials to better track the path of the virus, Dr. K. Fred Gingrich II, executive director of the American Association of Bovine Practitioners, an organization representing veterinarians who treat cows, previously told USA Today.

In July, Colorado’s veterinarians mandated bulk-milk testing to curb the spread of bird flu in the state’s dairy herds. Only one Colorado herd is infected with the virus at the moment, state data shows. Since April, a USDA order has required lactating dairy cows to be tested for bird flu before being moved across state lines. The order also requires all privately owned laboratories and state veterinarians to report positive test results. Friday’s order adds to the earlier order, according to the USDA.

This year, 58 people in the U.S. have been infected with bird flu, according to the Centers for Disease Control and Prevention (CDC). Of those, 35 have been dairy workers, and 21 have been poultry workers. All workers have had mild symptoms marked by eye redness. Two people, including a California child, have had unknown sources of transmission.

It is important to note that there has been no transmission reported between humans to date.

What is the National Testing Strategy?

The announcement launches the National Milk Testing Strategy that places states in one of five stages based on virus prevalence. Officials will work with each state in the contiguous U.S. to enact the testing. California, which has the most cases, along with Colorado, Michigan, Mississippi, Oregon and Pennsylvania will be included in the first round of testing under the new strategy.

Stage one begins the nationwide testing of milk silos at dairy processing facilities to first identify where disease is present. The system then moves to stage two to identify infected herds through bulk tank sampling, before stage three to rapidly respond to infected cattle using existing incentive programs, movement controls and contact tracing.

Once states can show their herds are no longer infected, federal officials will continue regular bulk tank samplings to make sure the disease doesn’t re-appear. Sampling will progressively decline as the state shows continued negativity. If bird flu does reappear, the state then has to return to stage three. After all states move through stage four, USDA will begin periodic sampling. The goal is to show long-term absence.


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