Many people who are infected with the roundworm have no symptoms of the disease. However, in patients who are taking proton-pump inhibitor antacids, steroids or are otherwise immunosuppressed, the worm can often diffuse throughout the body, causing symptoms throughout the digestive tract, in the lungs, and in the nervous system, often leading to shock. Diagnosis is difficult as the roundworm is not always present in feces. It is always found in the duodenum, but getting a sample from there requires an intrusive procedure.