Ref ID : 71
Pozio, E.; [Present knowledge of the taxonomy, distribution and biology of genera of Trichinella (Nematoda, Trichinellidae)]. Ann.Ist.Super.Sanita. 25:615-623, 1989
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The Trichinella genus, considered monospecific till 1972, is now composed of at least seven gene pools. The Soviet authors identified four of them as good species: T. spiralis, T. nativa, T. nelsoni and T. pseudospiralis. The biochemical approach identified three new taxonomic groups called Trichinella T3, T5, T6 on the operational level. Each gene pool has a well-defined distribution. T. spiralis only has a ubiquitous distribution due to passive importation caused by man. The life cycle of these nematodes unfolds inside of a single warm blood host. The ingested muscle larvae penetrate inside the columnar cells of the small intestine epithelium and develop into adult worms in four days. The females mate and produce 200-1,500 larvae (newborn) according to the species from the 5th-6th day. Through the lymphatic vessels, the newborn larvae reach the thoracic duct and get to the parenteral niche. The larvae, reaching the striated skeletal muscles, penetrate the muscle cells and begin a parenteral life. During the first 20 days the larvae increase from 80 microns to 1 mm. After this rapid growth, the larvae, growing infectious, survive in the muscle cell awaiting ingestion into a new host.