[jdadj]

I’m confused. How is wastewater from endangered animals ending up in the sewage system? Surely they’re not using toilets…

[ropeladder]

Sorry, my comment was a bit misleading: as the other commenter noted, they are doing testing in rivers, etc. When animals defecate/urinate onto the ground, some of it eventually gets carried and aggregated into flowing water.

[londons_explore]

There is always a little that drains in... Often these tests are done on river water too.

And PCR tests are super sensitive.