Trichinella spiralis is a parasitic roundworm that causes the disease known as trichinosis in humans. It is primarily transmitted through the consumption of undercooked or raw meat, especially pork, that contains encysted larvae. Once ingested, the larvae are released in the intestines, where they mature and reproduce. The larvae then migrate through the bloodstream to various tissues, particularly muscle, where they encyst and can remain viable for years. Symptoms of trichinosis can include gastrointestinal issues, muscle pain, and fever. Proper cooking of meat to safe temperatures can prevent infection from Trichinella spiralis.