Page:The New International Encyclopædia 1st ed. v. 19.djvu/525

* TRICHIASIS. 457 TRICHINIASIS. in plucking out tlic offending liairs (if they arc few in number) from time to time. Electrolysis may be employed. If tbey form a little group, they must be removed by dissecting out a por- tion of the lid and uniting the wound with a suture. In other cases it may be necessar}' to remove the entire margin of the lid. TRICHINA, trl-kl'nsi (Neo-Lat., from Gk. dpi^, thrix, hair). A peculiar nematode worm, wliich, in its sexually immature state, inlial>its the muscles of mammals, usiially the pig. It was discovered in 1835. The young trichinte. as they aje seen in human muscle, present the form of spirally coiled worms, in the interior of small, globular, oval, or lemon- shaped cysts, which appear as minute specks scarcely visilile to the naked eye. The cysts are sometimes altogether absent, and hence they must be regarded as formations resulting from local in- flammation set up by the presence of the worm, which in this larval condition of existence meas- ures about a millimeter long. These larval worms exhibit a well-marked digestive apparatus, and afford evidence of the presence of reproductive organs, which are often sufficiently developed to enable the observer to determine the sex. The number of larval trichinie that may simultane- ously exist in the muscles of a single man or animal is enormous. When an animal is fed with flesh containing the larval worm and is killed a few days after- wards, a large number of minute worms are found mixed with the contents of the small in- testines. On the second day after their intro- duction these intestinal trichinae attain their full sexual maturity, and in six days the females contain perfectly developed and free embryos in their interior. The female is a .slender round worm, varying in length from j'jto of an inch. The anterior end presents a bead like appearance, from which the intestinal canal proceeds. The posterior three-fourths are mainly occupied by the repro- ductive organ, which is tilled partly with free embryos, and partly with eggs in various stages of maturity. The females continue bringing forth young for a period of two or three weeks. The embryos penetrate the walls of the intestine, and pass either through the body cavity or by means of the blood-vessels into the muscles of the host, where, if the conditions are otherwise favorable, they are developed into the encysted form. Some of them reach the muscles of the extremities and other distant parts ; but the ma- jority remain in those sheathed muscular groups which are nearest to the cavity of the body ( abdomen and thorax ). especially in those which are smaller and most supplied with connective tissue. These embryos penetrate into the interior of the separate muscle fibres, and in the coui'se of fourteen days acquire the size and organiza- tion of Trirhi)ui spiralis. In the adult condition trichinre perish in cold water in about an hour, and cannot survive the decease of their host for more than six hours, but the larvrc remain alive in water for a month, and will live for a long time in flesh which has become putrid. In this way a carcass near a marsh or rivulet may com- municate the parasites to the ruminants that drink the water, or to pigs. The formation of the cysts is the cause of more or less serious injury to the host, according to the number pres- ent. Wlien abundant, the weakness is very marked and is often fatal. In man infection oc- curs, almost invariably through the eating of raw or underdone pork containing the cysts. If the meat is jiroperly conked the worms will be destroyed. Consult Braun, Die ticrischeii Para- sitcn (Ics Mctisrhcn ( Wiirzburg, 1002). See Par.vsite, AxiifAL. TRICHINIASIS. trik'inl'a-sis, or TRICH- INOSIS, -nf/sis (Neo-Lat., from Irirliiiui, trich- ina). A disease caused by the ingestion of food containing trichina (q.v.'), characterized by a numlier of puzzling symptoms. The disease was noted by Vormald. who saw the characteristic specks while dissecting subjects in Saint Bar- tholomew's Hospital; but its cause was demon- strated by Paget and the naturalist Robert Brown, in 18,3.5. Virchow (q.v.) first propagated the nematode in an animal and demonstrated its presence in the intestine in 1850. Leuekart in the following year presented a full, lucid, and complete solution of the whole question. After being swallowed, in pork, for example, the trich- ina worms traverse the connective tissue and gain access to all parts of the body. They are found, after death, in the muscles of the trunk and liead, as well as in the extremities; and most thickly placed in the diaphragm, the in- tercostals, the nuiscles of the neck (especially of the larynx) and of the eyes. The intestinal mucus also contains many. The intestinal canal shows catarrhal changes. The mesenteric glands are swollen. The heart muscle is almost in- variably free from invasion. The symptoms of the disease are as follows: On the second or third day after eating the in- fected meat the ]>atient suffers from nausea, vomiting, colic, and diarrh<Ta. Constipation may follow. The muscles then become weak, and great weariness is experienced. Between the tenth day and the sixth week the muscles become stiff, of a wooden consistency, and very tender. This con- dition is most noticeable in the flexors of the extremities, and occasionally the knees or elbows will be bent and rigid. The temperature gen- erally remains normal or is subnormal; rarely it rises, Q'^dema is characteristic and appears about the- seventh day, first in the eyelids and the face, next in the extremities. In the legs it may be extreme. It is probably due to toxins excreted by the parasites. Owing to the in- vasion of the larynx, hoarseness or aphonia is common, as also dyspnn>a, bronchitis, and pneu- monia. Profuse sweating is also characteristic. Acne, herpes, and boils may appear on the skin; pruritus is common. Insomnia is a common svmptom and is constant in severe cases. Head- ache occurs if pneumonia be present. S^¥ine suffer principally, among the lower animals; but rats, mice, rabbits, and guinea pigs are easily infected. Horses, cattle, sheep, goats, and dogs are with difliculty infected. It has been stated by some that rnts carry the parasites to swine. Cats are occasionally victims of trichiniasis. It is siipposed that the parasite gained access into Europe through the introduction of the Chi- nese pig early in the nineteenth century. The disease was epidemic in Syria in 1881. It has appeared in .Algiers; in South America; in th& West and JIassachusetts, in the United States;