Always present in a part of a large city and sometimes present in a smaller town that largely commutes into that larger city (the closest part) isn’t that strongly suggestive of a single person to me.
To complicate things, people flush more than poop down the drain. And poop with different regularity along with location preferences.
(The second thing being another reason why wastewater analysis is better for drugs/metabolites that excrete through urine)
It may not be a single person, but the individual(s) being infected exhibiting the same movement patterns would certainly be living together in close contact, and the lack of community spread supports the group of patients being very small, possibly just an individual.
To complicate things, people flush more than poop down the drain. And poop with different regularity along with location preferences.
(The second thing being another reason why wastewater analysis is better for drugs/metabolites that excrete through urine)