Part 106

Nodular disease of the intestine, due to young nodular worms which burrow in the intestinal wall during a certain stage in their life history, sometimes apparently produces serious effects, particularly in young cattle, but commonly has little or no perceptible influence on the general health. It, however, often renders the intestine unfit for use as sausage casings, and as it is widely prevalent among cattle the loss from this source is considerable. The greenish or yellowish nodules with cheesy contents are frequently mistaken by the inexperienced for lesions of tuberculosis.

The life histories of the various small roundworms occurring in the intestines of cattle, so far as they have been worked out, are very similar to that of the twisted stomach worm as described on page 519.

Treatment for intestinal roundworms.--The preventive measures are similar to those recommended in the case of the twisted stomach worm (p. 521). Medical treatment is generally not very satisfactory. According to the Oklahoma Experiment Station, the addition of 1 per cent of tobacco to the bluestone solution used in the treatment of stomach worms in sheep is effective in the removal of hookworms. The bluestone and tobacco mixture described on page 524 may be of value in the treatment of hookworms in cattle. It is asserted by one author that 2 or 3 drams of rectified empyreumatic oil in a mucilaginous emulsion, followed the next morning with a purgative of 1 to 1-1/2 pounds of sulphate of soda, will expel the large roundworms (Ascaris vitulorum).

PROTOZOA.

A number of species of protozoa have been reported as parasites of the intestines of cattle. To one species has been attributed a serious disease of cattle in Switzerland known as red dysentery, but so far comparatively few cases of this disease have been recorded in America. It is probably more common than is generally supposed. Calves particularly seem most likely to be affected.

FLUKES IN LIVER AND LUNGS.

Two species of flukes occurring in the liver and lungs are known to affect cattle in the United States. These parasites are flat, leaf-like worms; one of them, the common liver fluke (Fasciola hepatica, fig. 19), is less than an inch in length, while the other, the large American fluke (Fasciola magna, fig. 20), is considerably larger when full grown. In their life history these flukes depend on snails as intermediate hosts. At a certain stage of development the young flukes leave the snails, become encysted on stalks of grass (fig. 21), or fall into drinking water, and finally may be swallowed by cattle. Stiles writes as follows:

Flukes may produce a serious, often fatal, disease, more especially in younger animals. The symptoms are somewhat similar to those produced by worms in the stomach. The first symptoms are generally overlooked, the disease not attracting attention until the appetite is diminished; rumination becomes irregular, the animals become hidebound, and the coat dull and staring. The staring coat is due to the contraction of the muscles of the hair follicles. The visible mucous membranes become pale, eyes become dull, there is running at the eyes, and the animal gradually becomes emaciated. As the disease advances the milk supply is lessened, fever appears, there is generally great thirst, but the appetite almost ceases; edematous swellings appear on the belly, breast, etc.; diarrhea at first alternates with constipation, but finally becomes continuous. The disease lasts from two to five months, when the most extreme cases succumb.

Most of the German cattle are said to be infested with liver flukes, but even when a large number are present the nourishment of the cattle is not disturbed. Thickening of the gall ducts, so that a so-called "Medusa's head" forms on the surface of the liver toward the stomach, appears in even well-nourished animals; even in cases of a cirrhosis of the liver it is seldom that any effect upon the cattle's health can be noticed, and so long as a portion of the liver tissue about twice the size of the fist remains intact, the nourishment of the animal may be comparatively good. It is rare that one sees a generalized edema in slaughtered cattle as a result of fluke invasion, and even in the heaviest infections of young cattle only emaciation is noticed.

Treatment.--Medicinal treatment is unsatisfactory. The disease may be prevented to a considerable extent by giving animals plenty of salt, and by introducing carp, frogs, and toads into infected districts; these animals destroy the young stages of the parasite and feed upon the snails which serve as intermediate hosts.

The drainage of wet pastures and the avoidance of swampy lands for grazing purposes are important measures in the prevention of fluke diseases.

Railliet and others have recently recommended the application of lime to fluky pastures, having discovered that very weak solutions are destructive not only to fluke embryos but to snails. This application is to be made during the summer months at the rate of about 500 to 1,000 pounds of lime per acre. The same authors also recommend extract of male fern for the treatment of fluke disease. Moussu states that the average dose for cattle is 1 gram of the extract for each 10 kilograms of live weight; that is, 10 grams for a young animal weighing 100 kilograms (about 220 pounds) up to 50 grams as a maximum for large animals weighing 500 kilograms (about 1,100 pounds) or more. The extract is mixed with about 5 times as much non-purgative oil and the dose is administered each morning for five consecutive days two hours before the animal is allowed to feed after having been fasted over night. The extract of male fern used should have a guaranteed strength of 22 to 25 per cent of filicine and 3.5 per cent of filicic acid.

TAPEWORM CYSTS OF LIVER AND OTHER VISCERA.

Three kinds of tapeworm cysts are found in the viscera of cattle. One of these (Multiceps multiceps, or Cnurus cerebralis) will be further referred to in the discussion of gid (p. 528). All these are the intermediate stages of tapeworms, which live when mature in the intestines of dogs, wolves, and other canines. The eggs of the tapeworms are scattered over the fields in the droppings of infested dogs or wolves, and when swallowed in food or water by cattle hatch out and the embryos migrate to the liver, mesentery, lungs, brain, or other organs, where they develop into cysts, variously known as hydatids, bladder worms, water balls, etc. When organs of cattle thus infested are eaten by dogs or wolves the cystic worms are also liable to be swallowed and then develop into mature tapeworms. To prevent cattle from infection with these parasites stray dogs, wolves, and coyotes should be killed wherever found, and dogs too valuable to kill should be kept free from tapeworms. As a precaution against infection with tapeworms, the viscera of cattle, sheep, or hogs should not be fed to dogs unless cooked.

HYDATIDS (Echinococcus granulosus) form tumors (fig. 22) of varying size (sometimes as large as 6 inches in diameter) in the liver, lungs, and other organs. Their contents are liquid, resembling water. The presence of these parasites can not be detected in the living animal and there is no medicinal treatment for them. Organs containing hydatids should be destroyed by burning in order to prevent their being eaten by dogs. This is especially important, as dogs infested with the tapeworm stage of this parasite are a menace to human beings on account of the danger of infecting them with hydatids, which develop in man if the eggs of the hydatid tapeworm are swallowed.

THIN-NECKED BLADDER WORMS (TÊnia hydatigena, fig. 23) are most commonly found attached to the mesentery and omentum. There is no medicinal treatment.

GID.--Bladder worms (Multiceps multiceps, or Cnurus cerebralis), which are occasionally found in the brain of cattle and cause gid, "turnsick," or "staggers," deserve mention, as they are rather common among sheep in the Northwest. As already alluded to, these worms are the intermediate stage of a tapeworm found in dogs, and their life history and the means of preventing infection have been briefly discussed above (see p. 527).

Cattle harboring this parasite show symptoms indicating an affection of the brain, walking or turning in circles, dizziness, uneven gait, impaired vision, etc.

Treatment consists in trephining the skull and removing the parasite, an operation which requires a skillful operator and is frequently unsuccessful. Unless the parasite is removed affected cattle almost invariably die.

TAPEWORM CYSTS IN THE MUSCLES, BEEF MEASLES.

Small tapeworm cysts (TÊnia saginatÊ), about the size of a pea, found in the muscles of cattle are the larvÊ of the common tapeworm of man. Cattle become infected from feed or water which has been contaminated by the feces of persons harboring the adult tapeworms, and human beings in turn become infected by eating raw or rare beef infested with the larval stage (measly beef).

To prevent cattle from becoming infested with this parasite care should be taken that human feces are not placed where they will contaminate the feed or drinking water.

This parasite is very common in cattle in the United States, at least 1 per cent being infested. As a result considerable loss is entailed through condemnations of beef carcasses by meat inspectors, because of the presence of tapeworm cysts. All this loss could be avoided and the danger of tapeworm infestation in human beings from this source could be removed by the observance of proper precautions in disposing of human excreta. At the same time much sickness and many deaths from diseases (hookworm, typhoid fever, etc.) caused by soil pollution would be prevented, and farm life would be rendered much safer than under the poor sanitary conditions which are responsible for the high percentage of tapeworm cysts among cattle in the United States.

THREAD WORMS IN THE ABDOMINAL CAVITY.

Thread worms (Setaria labiato-papillosa) 2 to 4 inches long are frequently found in the abdominal cavity. They seem to cause little or no trouble. The embryos produced by these worms enter the blood vessels. According to NoÈ, they are spread from one animal to another by stable flies (see p. 503), but this has not been definitely proved. The roundworms found occasionally in the anterior chamber of the eye (see p. 531) are perhaps immature forms of this species which have reached this location during their migration.

LUNG WORMS.

Lung worms (Dictyocaulus viviparus, fig. 24) in cattle are thread-like worms 2 to 4 inches long, found in the bronchial tubes and producing a condition known as verminous bronchitis. The life history of the parasite is not fully known, but infection is evidently derived through the medium of pastures where infested cattle have grazed. In the later stages of the disease the cattle cough, especially at night. Young cattle are more seriously affected than old animals.

Treatment for lung worms.--Various treatments have been advocated for lung worms, including fumigating with different substances and injections of remedies into the trachea by means of a large hypodermic syringe or by a special spraying apparatus, but none have been very successful from a practical standpoint. About all that can be done is to feed affected animals well and protect them from exposure, removing them from the pasture and keeping them in dry yards or stables maintained in a cleanly, sanitary condition.