The case adds another worrying wrinkle to a global outbreak that has devastated bird and marine mammal populations, and recently appeared in cattle herds.
U.S. regulators confirmed that sick cattle in Texas, Kansas and possibly in New Mexico contracted avian influenza. They stressed that the nation’s milk supply is safe, saying pasteurization kills viruses.
The pandemic and recent wildfires have shown how unhealthy indoor air can be. But scientific and governmental inertia have slowed the necessary remedies.