Dear all,

I felt a bit ashamed the other day, after all these years working in sanitation, I couldn’t answer properly my 12 years old niece asking me “Why is there pathogens in the first place“

This is therefore a naïve question that I’d like to bring in this forum, hoping that biologist and anthropologists will have a clear and simple answer to it.

• Why is there pathogens in our digestive system that don’t make us sick when they are inside our stomach but do make us sick if we eat them ?

The cows are eating grass where they defecated the day before, I believe most farm mammals are not really affected by eating their own feces – what explains that in the natural selection process human this very big problem remained. Before being pathogens outside are they essantial to our digestion inside ? What about our cousins the apes, are they sick too if they eat their own feces or is it a human particularity ?

Thanks a lot for sharing articles or researches on the subject.

Wishing you all a good day.

Ben