Bird Flu in the US 2025: Airborne Spread, Dairy Cattle, and Farm Intervention Gaps

Science Friday explores the ongoing presence of H5N1 bird flu in the United States, highlighting persistent activity in backyard poultry, poultry farms, and migratory bird populations. Dr. Seema Lakhdawala explains how surveillance shifted away from cattle to wild bird flyways, the dynamics of milk testing, and the surprising finding that infected cows may show mild or no symptoms while still shedding virus. The conversation covers human risk to dairy and poultry workers, environmental reservoirs such as manure lagoons, and the potential for poultry vaccines. They also discuss policy fragmentation and practical guidance on safety around dead birds and raw milk.

Overview and current status

The episode provides a status report on the US bird flu situation, emphasizing that the H5N1 virus remains very much present, particularly among backyard poultry, poultry farms, and migratory birds. Egg shortages continue as states cull birds to contain outbreaks; the virus continues to circulate within the US and has not disappeared. The host notes that attention has shifted away from cattle, but the risk environment remains.

“the virus is continuing to circulate in the US” - Seema Lakhdawala

Surveillance, testing, and data gaps

The guest explains that federal surveillance was heavy during cattle outbreaks but has less visibility now that most detections are in migratory birds. When infections hit poultry farms, detection is rapid and mass culling follows to prevent broader spread. There is curiosity about ongoing milk testing programs and whether H5N1 appears in dairy milk without symptoms, as many cows are asymptomatic yet may shed virus.

“we detected an infectious virus in the air and in the manure lagoons” - Seema Lakhdawala

Transmission pathways and environmental reservoirs

The conversation emphasizes air as a transmission route, as well as manure lagoons where milk from sick cows can end up. The study (a preprint) found infectious virus in the air and lagoons, raising questions about wild birds' exposure when they drink or feed in lagoons. The panel discusses how migratory streams bring birds into contact with environments that may facilitate transmission, including fecal-oral routes common to H5 viruses.

“the more we let these viruses circulate in the wild, the more opportunity we give them to change and evolve and adapt to become successful in humans” - Seema Lakhdawala

Vaccines, interventions, and policy challenges

Vaccines exist for poultry, and Lakhdawala suggests that producers would adopt vaccination if it prevents losses from culling and outbreak disruption. The discussion highlights a key obstacle: federal agencies cannot mandate practices for private farms; only state-level authorities can, creating fragmentation that hampers proactive containment. The podcast also touches on PPE, education for backyard flocks, and the economic incentives that would favor preventive strategies.

“the more we let these viruses circulate in the wild, the more opportunity we give them to change and evolve and adapt to become successful in humans” - Seema Lakhdawala

Public guidance and takeaways

Listeners are advised to avoid handling dead birds, call animal control, and use appropriate PPE if contact is necessary. The host underscores pasteurization as a public health safeguard against raw milk exposure. The episode closes with a call for improved education, better political will, and proactive interventions to reduce spillover risks to poultry, cattle, and humans.