Parasites can certainly cause a wide range of different health problems. In part, this is due to the fact that there any many different kind of parasitic organisms that can affect human patients. Symptoms typically depend upon the type of organism and where it usually lives in a human host. There are many different tests that can be done to detect parasitic organisms. Since many of these organisms will live in the GI tract, stool studies are often used. In addition, blood tests can also provide an indication that the immune system is responding to a parasitic infection.
In your case, it sounds as though unrelenting hunger is itself a reason to visit a physician. Tapeworms that live in the intestines can cause a patient to be constantly hungry and losing weight, as much of the nourishment of the food you eat goes to feed the worm instead of your body. However, it is also possible for many other kinds of health issues to cause you to feel hungry. Your doctor
will want to know more about when this started, your other symptoms (for example, are you actually losing weight?), as well as your past health history and travel history. Hopefully you and your physician will be able to get to the bottom of what is causing your symptoms. The good news is that even if you do turn out to have a parasitic infection, there are many good antibiotic drugs that can used to eradicate them.