Regarding how exactly the mischief is done, it can be further dialectically analyzed.
The patient's stool has already been tested routinely and, generally, any parasites would have been detected. At the very least, their eggs could be found.
However, since neither parasites nor their eggs were found in the routine stool analysis, it's highly likely that the parasites are hiding in the small intestine, frantically absorbing the patient's nutrition, while producing substances that can cause the large intestine to bleed.
It could be larvae or some kind of hormone or harmful substance that can stimulate intestinal bleeding.
Considering that the patient has diffuse bleeding focused in the colon segment.
Zhou Can is more inclined to believe that parasites lurk in the small intestine, absorbing the nutrients they need from the intestinal fluid, then excreting irritant harmful substances that cause the large intestine to bleed.
