H5N1 dairy virus in waste water

https://www.scientificamerican.com/article/what-bird-flu-in-wastewater-means-for-california-and-beyond/
This article claims that they have known from about the beginning of the infection that the dairies were responsible for the high avian influenza in the waste water.  They even claim that milk is the primary source for the virus in city waste water.  Processing plants legally put some milk into the sewer system, and consumers dump milk down the drain.  They claim that they have known that infected dairies in the states that show high levels of virus in their waste water were responsible for the virus in the city waste water.  It seems criminal that no one started testing herds in states like Wisconsin and Florida that have shown virus in their waste water, but have not had their dairies tested for infection. Wisconsin is a big dairy state, but they aren't testing.  Florida have had poultry flocks go down with the dairy virus, have had virus positive dairy products produced in their state, and they aren't testing.
Ron Okimoto