type: timeline_event
On December 6, 2024, the USDA issued a new Federal Order requiring that raw (unpasteurized) milk samples nationwide be collected and shared with USDA for testing as part of a new National Milk Testing Strategy (NMTS) to address H5N1 in dairy herds. The order came nine months after the first detection of H5N1 in dairy cattle and after the virus had already spread to 720 herds across 15 states with 58 human infections, mostly farmworkers.
The Federal Order imposed three main requirements: sharing of raw milk samples upon request from any entity responsible for dairy farms, bulk milk transporters, bulk milk transfer stations, or dairy processing facilities; mandatory provision of epidemiological information by herd owners with positive cattle for contact tracing and disease surveillance; and mandatory reporting of positive results to USDA by private laboratories and state veterinarians.
The first round of testing under the new Federal Order was scheduled to begin the week of December 16, 2024, in California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania. This delayed implementation meant that comprehensive nationwide surveillance would not begin until more than eight months after the initial outbreak, allowing the virus to spread largely unmonitored across the country during the critical early months.
The order complemented but did not replace the April 24 Federal Order, which required mandatory testing of lactating dairy cows prior to interstate shipment. However, the April order had proven insufficient to track or contain the outbreak, as it focused only on cattle movement rather than comprehensive surveillance of the milk supply. The December order represented an acknowledgment that the previous approach had failed to prevent widespread transmission.
Critically, the testing program focused on raw milk destined for pasteurization, with the USDA and FDA maintaining that pasteurization would inactivate any virus detected. Milk that tested positive would not be destroyed but would be sent on for pasteurization, raising questions about whether the program prioritized industry economic interests over more precautionary public health approaches.
The nine-month delay between the first detection of H5N1 in dairy cattle and the implementation of mandatory nationwide milk testing represented a significant regulatory failure. During this period, the virus spread unchecked through dairy herds across multiple states, infected dozens of farmworkers, and created sustained contamination of the milk supply. The belated testing requirement demonstrated how regulatory agencies prioritized industry concerns about economic disruption over rapid implementation of comprehensive disease surveillance, allowing a novel public health threat to become entrenched in the agricultural system before comprehensive monitoring began.