Parasites of course are worms, or anything that lives off a host. Worms of course will give you the itchy butt, give you a stomach ache sometimes, but usually that is about
it. For the most part, worms will stay in your digestive track. When doing a cleanse for them, they are usually visible in the stool.
There are other parasite that are micro-organisms, remain small, and hide/grow within organs. For instance, a liver flute, will invade your gall bladder, invade bile tubes, and go into your liver. It may also travel into other organs such as your kidney, adrenal glands, heart muscles, etc. The mico- organisms are the nasty ones that caused all the problems that I experienced. Where ever they go, they deposit eggs.They are very difficult to detect. When they check for these types of parasites, it is again by way of a stool sample, but they are not looking for the actual parasite, they are looking for eggs. The eggs may or may not be in the stool sample - as they do have a tendancy in just staying in little sacks and attach themselves to the walls of organs, etc. The eggs tend to be quite toxic, and the more of them that remain in your body, the more sick you become. And lets say that the egg sacks are in the pancreas as an example, then you are likely to have pancreas/insulin problem.
Sometimes these egg sack will show up as shadow on a CT Scan, but again, not very often...So when your doctor throws his hands up saying he does not know (which mine did!) yet things are just falling apart on you - I would investigate the possibility of micro-organism type parasites.
Again,just my two cents worth,