The inspection of meats for animal parasites / prepared under the direction of D.E. Salmon.

Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: The inspection of meats for animal parasites / prepared under the direction of D.E. Salmon. Source: Wellcome Collection.

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    Round worms (Nemathelminthes). The Flat worms alone are discussed in this report. Flat Worms (Class Plathelminthes). The Flat worms include at present five orders, only two of which, namely, the flukes (Trematoda) and the tapeworms (Cestoda), are discussed in this report. Flukes, or Trematodes.—Tbe flukes found in cattle, sheep, and swine vary in size from a few lines to 4 inches in length and from one or more lines to an inch or more in breadth. They are found in the liver, lungs, intestine, and body cavity, and occasionally in other parts of the body. None of the species found in cattle, sheep, or swine are directly transmissible from these animals to man, although three of the species occasionally infest man. At least two of the species render the organs in which they occur unfit for food when present in numbers; they also injure the animals to a greater or less degree, although the extent of injury in cattle has possibly been overestimated; one form is particularly injurious to sheep. 'Tapeworms, or Cestodes.—Cestodes occur as larval forms (blad- der worms) or as adult forms (tapeworms, strobilae). Larval tapeivorms.—The larvae, or bladder worms (Gysticercus, Coenu- rus, Echinococcus), are found in the liver, lungs, brain, muscles, or other organs except the intestinal tract, and do not reach maturity until they are transmitted to meat-eating animals. The most important bladder worms considered in this report are: (1) The Beef-measle Bladder Worm, and (2) the Porh-measle Bladder Worm, both of which develop into tape- worms in man; (3) the Gid Bladder Worm, which causes gid, or turn- sick, in sheep; and, (4) the Hydatid, which causes hydatid disease in man and various domesticated and wild animals. When eaten by dogs the two latter bladder worms develop into Adult tapeworms. Adult tapeivorms.—Several different species are found in the intes- tine of cattle and sheep. They injure their hosts, but are not trans- missible to man in any stage of their development. The following key will aid the reader in determining the various flukes and tapeworms discussed in this report. A certain amount of technical knowledge is valuable in the use of this key, which is based upon zoological characters. Some liberty has, however, been taken with the anatomical characters in order to make the key as simple as possible; and it is believed that most, if not all, of the forms mentioned can be more or less definitely determined by comparing the key, espe- cially the habitat given for each form, with the figures of the parasites, even if one is unable to follow the more technical statements. Key to the Flukes and Tapeworms of Cattle, Sheep, and Swine. [For the species thus far positively known to have been found in North America, follow Roman type. As the characters given are confined to the forms discussed in this report, this key should not be relied upon to classify the parasites of other animals.] (1) Parasitic in the liver, lungs, pancreas, veins, abdominal cavity, or intestine of cattle, sheep, and swine, more rarely encysted in muscles of swine. Unseg- mented Flat worms; intestinal tube present; anus absent; mouth with one sucker Flukes, 2.