Triclinium

“ Tiedemann (1822) , Peacock (1828) described “little bodies” in the muscles of human cadavers which Hilton (1832) considered to be parasitic in nature. Paget (1835) showed that these bodies were round worms and Owen (1835) described them more accurately and gave the name Trichina spiralis to them. Leidy (1846) found organisms in the muscles of hogs which he considered to be the same as Owen’s Trichina and paved the way for the work of Zenker (1860) in showing the pathological relation between the Trichina of pork and human Trichinosis. ”

“ I had myself examined the trichinised flesh taken from a dozen of these corpses, but in no instance had the faintest suspicion of trichinosis been entertained during life. The circumstances attending the only outbreak of trichiniasis that has been witnessed in England are very interesting. In the month of April, 1871, I received from Dr W. L. Dickinson, of Workington, Cumberland, specimens of pork which he requested me to examine; and in complying with his request I confirmed his opinion that the diseased meat was infested with Trichinæ. ”

“ The Trichina (Fig. 25) lives in its immature condition in a sac. These sac-like bodies are found in the pig, the meat of which, if not sufficiently cooked when eaten, will cause this very fatal disease, as the sac being destroyed by the juices of the intestine, the young Trichina is set free, and deposits eggs, the embryos from which bore through the viscera of the unfortunate one. The Trichina belongs to the family of thread-worms or Nematoda. ”

“ Trichina spiralis is the juvenile state of a little round worm, previously unknown, to which the generic title of Trichina must remain attached. (2) The sexually mature Trichina inhabits the intestinal canal of numerous warm-blooded animals, especially mammalia (also of man) , and constantly in great numbers. The duration of its life extends from four to five weeks. (3) At the second day after their introduction the intestinal Trichinæ attain their full sexual maturity. ”

“ Such infested muscle or flesh is said to be "trichinosed," and the flesh of a trichinosed human subject has been estimated to contain 100,000,000 encysted worms. To complete the development of the encysted and sexless Trichinæ the infested flesh of the host must be eaten by another animal in which the worm can live, e.g. the flesh of man by a pig or rat, and that of a pig by man. In such a case the cysts are dissolved by the digestive juices, the worms escape, develop reproductive organs and produce young, which then migrate into the muscles and induce trichinosis as before. ”

“ Take, for instance, the trichina spiralis, a minute worm discovered in 1835 encysted in countless numbers in the muscles of the human body; it was studied by Virchow, Leuckart, and others, by feeding-experiments on animals, and was proved to come from infected 245 half-cooked ham and pork, and to make its way from the alimentary canal all over the body. The name of trichiniasis or trichina-fever was given to the acute illness that came of the sudden dissemination of these myriad parasites into the tissues. Trichiniasis had killed hundreds of people by a most painful death ”

“ Trichina, tri-kī′na, n. a parasitic worm, which in its mature state infests the intestinal canal, and in its larval state the muscular tissue of man and certain animals, esp. the hog:—pl. Trichī′næ:—ns. Trichinī′asis (more usually Trichinō′sis) , the disease caused by the presence of trichinæ in the body; Trichinisā′tion.—adjs. Trich′inōsed, Trichinot′ic, Trich′inous. [Gr. trichinos, small like a hair—thrix, trichos, hair.]
Trichite, trī′kīt, n. a spicule of some sponges.—adj. Trichit′ic.
Trichiurus, trik-i-ū′rus, n. the genus of hair-tails. ”

“ Nor was the full story of the trichina made out for a long time after Owen's discovery. It was not till 1847 that the American anatomist Dr. Joseph Leidy found the cysts of trichina in the tissues of pork; and another decade or so elapsed after that before German workers, chief among whom were Leuckart, Virchow, and Zenker, proved that the parasite gets into the human system through ingestion of infected pork, and that it causes a definite set of symptoms of disease which hitherto had been mistaken for rheumatism, typhoid fever, and other maladies. ”

“ Trichiniasis or trichinosis is a disease characterized by fever, muscular pains, an enormous increase in the eosinophil blood corpuscles, and other more or less well-defined symptoms; at the onset it is sometimes mistaken by physicians for typhoid fever. The responsible parasite is a roundworm (Trichinella spiralis, formerly known as Trichina) which is swallowed while in its encysted larval stage in raw or imperfectly cooked pork. ”

“ Trichiniasis is generally accompanied by a marked eosinophilia. The diagnosis is made by teasing out upon a slide a bit of muscle, obtained preferably from the outer head of the gastrocnemius, the insertion of the deltoid, or the lower portion of the biceps. The coiled embryos can easily be seen with a two-thirds objective (Fig. 108) .
(5) Uncinaria.—The two varieties of this worm, Uncinaria duodenalis and Uncinaria Americana, are among the more harmful of the animal parasites. They inhabit the small intestine, usually in great numbers, and commonly produce a severe and often fatal anemia. ”

“ The males after a time leave the body with the excreta and perish, whilst the larvae of the new brood make their way into the tissues of the host.
Man usually acquires trichinosis by eating uncooked or improperly-cooked pork, and the disease is so widely spread and of such a serious nature that most civilised countries have adopted rigorous methods for the detection of trichinised meat. ”

“ Diagnosis in the presence of several cases, or in epidemics, is not difficult, but in isolated cases, on the other hand, it is not easy. If there is a suspicion of trichinosis, from the muscular fatigue and the œdema of the eyelids, the diagnosis can be made by excision of a piece of muscle and by finding the Trichinæ in the tissue, taken with the results of the examination of the previously eaten sausage or meat. ”

“ Cases of trichinosis have been known to occur in nearly all the countries of Europe; further, in Egypt, Algeria, East Africa, Syria, India, Australia, and America. North Germany, more especially the Saxe-Thüringian states, is the classical land for epidemics of trichinosis; the mortality varies, but it may be very high.306
Prophylaxis.—The grave nature of the disease and the comparatively high mortality relating to trichinosis led the authorities to adopt certain preventive measures, which are the more necessary as national customs cannot be altered in a short time. ”

“ Muscular trichinosis is unknown in fishes, but the sexual form develops in their intestine.
The adult parasites of the intestine are scarcely visible to the naked eye; the females are 3 to 4 mm. long and more numerous than the males, which measure 1.4 to 1.6 mm. The eggs are very numerous, a single female containing at one time 1200, and probably producing ten times as many during her life. ”

“ To place matters beyond all doubt much remains to be done; yet that which has been accomplished is, or ought to be, of surpassing interest alike to the physician, the scientific pathologist, the epidemiologist, and the philosophic naturalist. In the case of Trichina, Owen’s nomenclature was most properly allowed to stand; but for reasons stated below I have not hesitated to employ for this worm, in its adult state, a name differing from that originally given to the hæmatozoon which turns out to be its representative larval state. ”

“ The female sexual cell is represented by the contents of a cell which is terminal on ordinary or specialized branches. This is the carpogonium; it consists of a ventral portion which contains a nucleus, but in which no oosphere is differentiated, and an elongated tubular portion known as the trichogyne, into which the cytoplasm extends. Fertilization is effected by the passive convection of a spermatium from the antheridium to the trichogyne, to which it adheres, and to which it passes over its nucleus through an open communication set up at the point of contact. ”

“ The larva of the tænia saginata is found in the muscular fibers and connective tissue of cattle and when ingested in man develops into the tænia saginata.
Trichinosis
There is a parasite known as trichina spiralis which is found as a minute spiral worm in the muscular fibers of pork. It is visible to the naked eye as white specks. The ingestion of this parasite into a person with subluxations, causing interference with transmission of mental impulses, produces a condition which is called trichinosis. It is an acute condition and the symptoms resemble typhoid fever. It often results fatally. ”

“ Henceforth he continued to make important contributions to every department of comparative anatomy and zoology for a period of over fifty years. In the sponges Owen was the first to describe the now well-known " Venus's flower basket " or Euplectella (1841, 1857) . Among Entozoa his most noteworthy discovery was that of Trichina spiralis (1835) , the parasite infesting the muscles of man in the disease now termed trichinosis (see also, however, the article on Paget, Sir James) . ”

“ The further development of the muscle-Trichinæ into adult animals is altogether independent of the formation of the calcareous shell, and occurs as soon as the former have reached their completion. (14) Males and females are already recognisable in their larval state. (15) The immigration of the Trichina-brood in masses produces very grave or even fatal consequences, such as peritonitis (from the embryos perforating the intestinal walls) , pain, and paralysis (resulting from the destruction of the infected muscular fibres) . (16) The infection of man occurs especially through swine. ”

“ The young brood is distributed from the heart throughout the entire body, but the conditions necessary to its further development are found only in striated muscle; the young Nematodes penetrate the capillaries, attain the intramuscular connective tissue and then invade the fibres (Virchow, Leuckart, Graham304) . On the ninth or tenth day after infection the first Trichinellæ have reached their destination; but further invasions are constantly taking place because the intestinal Trichinellæ live from five to seven weeks, and continue to produce their young. ”

“ A high temperature (30°C.) must be provided in which to keep the experimental animals to ensure the success of the infection.
Fig. 302.—Trichinella spiralis. ♀, mature female: E, embryos; V, vulva; Ov, ovary. ♂, mature male: T, testes. c., newly born larva. d., larva in the muscles. e., encapsuled larva in the muscles. Magnified. (After Claus.)
History.—Encapsuled Trichinellæ had been observed in London by Peacock (1828) and by J. Hilton (1833) in the muscular system of man ”

“ Within the muscles the parasites do not undergo further development. Gradually the capsule becomes thicker and ultimately lime salts are deposited within it. This change may take place in man within four or five months. The trichinae may live within the muscles for an indefinite period. They have been found alive and capable of developing as late as twenty or twenty-five years after their entrance into the system. These calcified capsules appear as white specks in the muscles. In many instances however these worms are completely calcified. In the hog the trichinae cause few if any symptoms. ”

“ Sporadic outbreaks of this incurable disease have occurred at various times and of variable intensity, but always with the most alarming results.
Unfortunately we possess no means of detecting the trichinæ when they have once been introduced into the system; we may by the symptoms be led to suspect that they are present, but that is as far as we can go; and if we are to believe Professors Delpech and Reynal it is utterly impossible to discover them; they affirm, however, that in cut meat the larval capsules, or lemon-shaped cases, can only just be seen by the aid of a powerful lens. ”

“ Recovery from these phases of trichinal infection may be apparently perfect. A rabbit which M. Davaine kept during five months became large and fat, although it had a large number of Trichinæ in its muscles; a rat which had had these entozoa in considerable numbers during six months was, to all appearance, in good health. Hence he concludes that the Trichinæ produce symptoms only when they are in the intestinal canal, and when they are entering the muscles. Having become lodged in their cysts among the muscular fibres, they may remain harmless for an indefinite time. ”

“ In the same way calcareous infiltration sometimes occurs, but only when the parasites have lost their vitality. This calcareous degeneration consists in the deposit of carbonate and phosphate of lime in the walls of the cyst; it never begins before the seventh or eighth month after infestation, and is sometimes much longer delayed.
No man or animal ever becomes infested except by the ingestion of meat or drink containing larval trichinæ. The pig and small rodents are most frequently attacked. Man contracts trichinosis by eating insufficiently cooked infected pork. ”

“ T. nodosus in mouse; T. alcocki in the thamin (India) ; T. globulosa in camel; T. giraffæ in giraffe.
Sub-family. Trichinellinæ, Ransom, 1911.
Male without spicule; females ovoviviparous. Larvæ penetrate muscles of host and become encysted. Genus: Trichinella.
Genus. Trichinella, Railliet, 1895.
Syn.: Trichina, Owen, 1835 (nec Meigen, 1830) .
Very small Trichinellinæ, the males of which have two conical appendages at the caudal extremity; the vulva is situated at the border of the anterior fifth of the body. There is only one species.
Trichinella spiralis, Owen, 1835. ”