What is the history and life cycle of trichinosis?
The life cycle of this particular parasite is important in the way disease develops in humans. In 1835, J. Paget and R. Owen first discovered larvae of Trichinella in a piece of human muscle during an autopsy. That same year, R. Virchow and F. Zenker discovered the complicated lifecycle of Trichinella by feeding a dog Trichinella-infected meat. In humans, the larvae are ingested, released from an encapsulated (encysted) cyst by stomach acid (except for the nonencapsulated T. pseudospiralis), and then develop into adult male and female worms in the gastrointestinal tract. The adult worms mate and then shed larvae that penetrate the gastrointestinal tract and reach the bloodstream and lymph drainage system. The larvae are then distributed to body cells (mainly skeletal muscle cells). Some skeletal muscle cells develop into nurse cells that support and protect the larvae from the host’s immune system. For a more complete description of the life cycle that requires at least two hosts, plea
