TRICHINOSIS or TRICHINIASIS, a disease, in man and other animals, caused by infection by the parasite Trichina or Trichinella spiralis. The presence of encysted trichinae in the muscles was discovered by Sir James Paget (q.v.) in 1835, and they were named by Sir R. Owen; but it was not until 186o that the clinical characters of the acute disease caused by the invasion of the parasite were discovered by Friedrich von Zenker (1825– 1898). Epidemics of this disease have occurred from time to time, especially in north Germany, from the eating of uncooked swine's flesh, in which trichinae are not uncommon.
The symptoms in man are occasioned by the presence of the free parasites in the intestine, by the development of young trichinae from the eggs, and most of all by the migration of the parasites from the intestinal canal to the muscles, where they become quiescent. This cycle occupies from four to six weeks. Lime-salts become deposited in the capsule, the calcification rendering the cyst visible, and this change usually takes five or six months. When consumed in small quantity, the parasites may
give rise to no symptoms. In more serious cases, sometimes end ing fatally, the early symptoms are nausea, failure of appetite, diarrhoea and fever; later, when the migration to the muscles begins, there is more fever, stiffness, pain and swelling in the limbs, swelling of the eyelids, continued exhausting diarrhoea, perspiration and sometimes delirium. The existence of a marked leucocytosis with an extraordinary increase of eosinophiles helps diagnosis in cases where the symptoms are obscure. If the diag nosis be made early in the case, brisk purgatives, particularly calomel, are the best treatment; if the parasites are already on their way to the muscles, the only thing left to do is to support the patient's strength.