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Worms

found, distoma, parasite, intestinal, worm, filaria, common and hepaticum

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WORMS. These parasitic animals are usually located in the alimentary canal ; although the term may be extended sufficiently to include also those forms of worms which are known to burrow into the skin, or may even be found in the eyes, blood-vessels, liver, lungs, muscles, connective tissue, kidneys and brain. Those parasites which inhabit other localities than the intestinal canal are comparatively infrequent except in the tropics. Thus, the Filaria Medinensis and the hook-worm or Uncinaria have been found in the skin, whereas the Filaria loa, the Cyst-icercus, Trichina, and the larvae of tapeworms have been found in the eye as well as in the brain. The cysticercus as well as the echinococcus larva of the tapeworm are known to occur in almost all tissues of the body, giving rise to very characteristic and often fatal symptoms. They are, however, described in the article on TAPEWORM, and also in the article on FILARIA, to which reference may be made. The blood is the site of a very interesting animal, the Filaria Bancrotti, one species of which is recorded as occurring in the United States, although its chief habitat is in Africa and Europe.

A number of forms of worms are known to make the liver their home. Practically few of these are as yet known to occur in mild climates, although the flukes (the Fasciola hepaticum and the Dicrocoeliztin lanceolatum of Southern Europe, and the Paragonimus IVestermanni of Asia) are known to be present in other hosts than man ; and hence it is not at all unlikely that they may some clay be found in the human species.

Flukes. The Fasciala hepaticum, or Distoma hepaticum, is a common parasite of the ruminants. It is a small worm, being only z to V. inches in length. A related species, Distoma (Dicrocoeliant) lanceolatum, is found very commonly in cows and sheep in Europe ; while in Japan there is a Distoma which is widely distributed among cattle, and affects human beings as well. In certain provinces in Japan it has been estimated that this parasite (Distoma sinense) is present in twenty per cent. of the population. The Distoma telineum is a frequent parasite among Russians ; and it has been found among cats in Nebraska. For the most part the flukes thrive best in the liver, particularly in the bile-ducts, and often give rise to fatal jaundice with dropsy. The ova may be found in the stools. In another fluke-disease, caused in Asia by the Distoma (Paragonimus) Westermanni, the parasite lives in the bronchial tubes and gives rise to cough and pneu monia, with bleeding from the lungs. It is an epidemic affection. The

genito-urinary organs are the site of another fluke, the Bilharzia, which causes symptoms of pain on urination, associated with bloody urine, and anemia.

A large number of pseudoparasites belonging to the class of worms have been found from time to time. These, however, should be regarded as incidents of accidental parasitisni, often brought about by swallowing the larva of these animals. Thus, a minute worm, which is a common inhabitant of fresh-water pools, is swallowed quite often, and, living for from ten to twenty hours, may be vomited or passed in the faeces, and taken for a genuine parasite. It cannot, however, maintain a separate existence in the intestinal canal. The same may be said of a number of larwe of insects, the arachnids, etc.

Roundworms.—Another class of worms is that of the nematodes, to which the common roundworm (Ascaris lumbricoides) and the pinworm or seat worm (Oxyuris verinicularis), belong. The Ascaris is one of the most frequent of the intestinal parasites. The worms are small, the male being from 4 to 8 inches in length, the female double that size. It is long and thin, resembling an earth-worm, and has four longitudinal bands and many transverse rings and ridges. The eggs, which arc very numerous, are small, only -sh. of an inch in diameter, and are elliptic in form with a distinct covering. The roundworm lives in the upper part of the small intestine, and no intermediate host is known. As a rule only a few worms are present, although occasionally a patient harbours a great many. Living best just below the opening of the stomach into the intestine, the worm not infrequently gets into the stomach, from whence it may be vomited. The symptoms are none at all, or those of mild indigestion. In however, there may be marked nervousness, restlessness in sleep, and even convulsive seizures from intestinal irritation. Picking at the nose, twitchings, and marked mental distraction may also be observed. Diagnosis is made by microscopical examination of the stools. The treatment for roundworm is always difficult, as only a few anthelmintics are available. These are santonine, spigelia, and chenopodium ; but they should be administered only on a physician's prescription.

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