A lot of H5 detections in wastewater surveillance in California.

Makes sense with the widespread H5N1 outbreak in dairy farms in the state (wastewater surveillance doesn't distinguish between human/animal source).

If there is a silver lining, rest of the US isn't seeing detections. So unlikely there is much cryptic transmission like we saw during the early days of the coronavirus pandemic.

The usual influenza surveillance can pick up H5N1. That's how we picked up two human cases so far. The standard tests at your doctor's office can't differentiate H5N1 from seasonal flu, but will be positive for influenza A. Public health labs and the CDC have tests to do subtyping to differentiate suspected cases.