The worms are being well fed. The body is only getting the water and the calories but a fraction of the nutrients. In a Nutritional Almanac printed by McGraw-Hill and reproduced in part below, we read worms irritate the intestinal lining and therefore cause poor absorption of nutrients. Signs of worms may include diarrhea, hunger pains, appetite loss, weight loss and anemia. Pin worms are transmitted when the eggs, which lodge under the fingernails when a person scratches, contaminate food.
Personal hygiene is most important for the control of pinworms.
Tapeworms can be contracted from eating insufficiently cooked meats, especially beef, pork and fish. Hookworms are often found in the soil or sand in moderate climates. They can enter the body by boring holes in the skin of bare fee, or can enter the mouth if food contaminated by dirty hands is eaten. A quarter of the worlds people have hookworms, which can cause anemia and abdominal pain. Another third of a billion people suffer from abdominal pain and diarrhea caused by whipworms.