Trichinosis is a common infection worldwide. A person can get trichinellosis (trichinosis) after eating improperly cooked meat infected with the worm Trichinella spiralis. When a person eats meat from an infected animal, trichinella cysts hatch in the intestines and grow into adult roundworms. The roundworms then produce offspring that migrate through the lining of the intestines and into the bloodstream. These parasites invade muscle tissues, including the heart and diaphragm.