The incidence of Trichinella spiralis in the diaphragms of swine from the Louisville abattoirs.
Date on Master's Thesis/Doctoral Dissertation
College of Arts and Sciences
Trichinosis in animals--Kentucky--Louisville
Trichinosis is a disease caused by the parasitic nematode Trichinella spiralis. When meat containing encysted larvae is consumed the cysts are dissolved by the action of the gastric juice in the stomach and the larvae migrate to the intestine where they mature, copulate and give birth to living young within a week of the original infection. The larvae enter the lymph spaces and are carried to the thoracic duct from which they reach the venous circulation and thence the arterial circulation by way of the heart and the pulmonary capillaries. From the arterial blood the larvae enter most of the striated muscles. After entering the muscle fibers the larvae grow rapidly, become spirally coiled, and in 4 to 6 weeks a membranous capsule begins to form around each worm. If the infested host remains alive, the cyst wall usually begins to calcify in 8 to 10 months. Eventually the entire cyst becomes calcified and the larvae die. The presence of encysted trichinae larvae in the muscles of man was probably first noted by Tiedemann in 1822, although he failed to recognize their significance. John Hilton in 1833 was the first to suggest the parasitic nature, although the actual discovery of the worm was made in 1835 by James Paget who saw the calcified larvae in cadavers at St. Bartholomew’s Hospital and found upon microscopic examination that they contained a coiled roundworm. Paget’s discovery was reported by his teacher, Robert Owen, who called the parasite, Trichina spiralis.
Adams, Stuart Lyle, "The incidence of Trichinella spiralis in the diaphragms of swine from the Louisville abattoirs." (1942). Electronic Theses and Dissertations. Paper 1657.