Trichinella spiralis
Trichinella spiralis is a nematode parasite, occurring in rats, pigs, and humans, and is responsible for the disease trichinosis. It is sometimes referred to as the "pork worm" due to it being found commonly in pork or rat products that are undercooked.
-Life cycle
Larvae encysted in the muscles remain viable for some time. When the muscle tissue is eaten by a human, the cysts are digested in the stomach; the released larvae migrate to the intestine to begin a new life cycle. Female trichina worms live about six weeks and in that time may release larvae. The migration and encystment of larvae can cause fever, pain, and even death because of their potential to eat living tissue. One of the classic signs of Trichinella spiralis infection is a combination of splinter hemorrhages (not to be confused with those of bacterial endocarditis) and periorbital edema (eye swelling). Trichina are classified in the phylum Nematoda, which includes Caenorhabditis elegans, an important scientific model organism for studying genetics behind various topics such as development, neuroscience, disease, and aging.
-Symptoms
The first symptoms may appear between 12 hours and two days after ingestion of infected meat. The migration of worms in the intestinal epithelium can cause traumatic damage to the host tissue and the waste products they excrete can provoke an immunological reaction.The resulting inflammation can cause symptoms such as nausea, vomiting, sweating and diarrhea. Five to seven days after the appearance of symptoms facial edema and fever may occur. After 10 days intense muscular pain, difficulty breathing, weakening of pulse and blood pressure, heart damage and various nervous disorders may occur, eventually leading to death due to heart failure, respiratory complications or kidney malfunction.
-Diagnosis and treatment
Muscle biopsy is used for trichinosis detection. Several immunodiagnostic tests are also available. There are currently no satisfactory treatments for trichinosis, however symptoms can be relieved by use of analgesics and corticosteroids.