Do human parasites in human poop spread to more humans animals fed on plants fed on human poop, or only of humans eat the plants fed on human poop?
Can the parasites be filtered away?
Also, couldn't NK parasites be explained by a general lack of health and hygiene technology in NK? Parasites are a major problem in large parts of Africa too, but are controlled when medications are deployed.
Some parasites are human specific, but a lot of them will manage just fine in many mammals. Health and hygiene is likely a major factor, but managing human waste in a sanitary way is one of the big jobs of community health and hygiene efforts; that and access to clean water. Proper health protocols wouldn't allow for untreated night soil to be used as fertilizer, but maybe they don't have access to treatment or other fertilizer, so there you go.
Can the parasites be filtered away?
Also, couldn't NK parasites be explained by a general lack of health and hygiene technology in NK? Parasites are a major problem in large parts of Africa too, but are controlled when medications are deployed.