FOR THE FARMER.

Manawatu Standard, Volume LX, Issue 158, 5 June 1940, Page 12

FOR THE FARMER.

INTERNAL PARASITES OF PIGS. LARGE INTESTINAL ROUNDWORM (Written for the “Standard.”) The large intestinal roundworm, Ascaris sius, is a large, thick, yellow or pink worm, about the size of an ordinary lead pencil. The normal location of the adult parasites is the small intestine; wandering adults may occur also in the stomach, in the lower portion of the alimentary canal, in; the bile, ducts of the liver, in the gall bladder, and in other parts; of the body which have channels of communication with the gut. The young migrating worms occur in the blood stream, the liver, lungs, and other orgaiiß and tissues. The adult female produces thousands of eggs daily. It has been estimated that a single full-grown female worm in the intestine of a pig may contain between twefity-six and twenty-seven million eggs. The eggs are eliminated from the pig’s intestine with the droppings and are not infective until they have undergone development in the open. Under favourable conditions of temperature and moisture, the eggs reach the infective stage ill about three to four' weeks; under unfavourable conditions, such as low temperatures and lack of moisture, the development of the eggs may be prolonged to several months. When the eggs have attained the infective stage, a tiiiy worm already undergoing a moult is contained in the eggshell. Pigs become infested with asoo.ri.ds by swallowing the infective eggs with feed and water. Ascarid eggs are abundant ’ in yards and on pastures previously occupied by infested pigs and hence contaminated with their droppings. The young worms present in the eggshells become free in the pig’s intestines. These microscopic worms penetrate the wall of the intestine and travel in the blood stream to th? liver, and'from the liver to the lungs; in the lungs the worms leave the small blood vessels and get into the air spaces. the air spaces in the lungs the worms travel upward along the branches of the windpipe, in the windpipe proper, reach the back of tile mouth, and are swallowed. On getting back into the intestine they settle down and grow to egg-laying maturity in about two to two and a-half months. If many young worms make this curious roundabout journey at the same time, the resulting injury to the lungs is likely to be very serious and may prove fatal in the case of very young pigs. . _

Damage produced.-—Roundworms in the intestine may produce digestive disturbances and a capricious appetite, retard growth and development, and interfere ryith the well-being of the pigs in many ways. In exceptional cases, particularly when pigs are on an inadequate diet, infested animals may become anaemic, suffer from colic, and in extreme cases they may suffer from convulsions.. During the migration of young ascarids through the lungs, pigs have great difficulty in breathing and may die of pneumonia. I’igs that survive a severe infestation of the lungs with ascarid larvae may not recover fully, and often fail to grow and develop at a normal rate. Young pigs are far more susceptible to ascarids than full-grown animals, and very young pigs suffer seriously from the effects of these parasites. Although the damage to the liver and lungs done by migrating larvae heals as a rule, the liver is sometimes permanently affected by the .massive migration of young worms. The repair to the damage results in numerous scars, the entire surface of the liver becoming peppered with whitish areas. In some lots of infested nigs as many as 40 per cent, of the livers have been found thus affected. Treatment.—The most satisfactory treatment for the removal of ascarids from the intestines consists 'in the administration with a dose syringe or by means of a stomach tube of wormseed oil (oil of chenopodium) at the rate of one-half to 1 fluid dram (2 to 4 cubic centimetres) to a 100 pound animal, immediately preceded, or followed by at least 2 fluid ounces (60 cubic centimetres) of castor oil, or the drug may be administered in the oil. Some veterinarians substitute calomel or aloes for castor oil; others use Glauber’s salt or Epsom salt in solution in grain, or in sloppy food at the rate of 1 pound of salts to 10 pigs, three hours after treatment. Although doses for animals of various sizes are usually computed oil the basis of Weight, it is likely that a dose of 2 fluid drams of oil of chenopodium is sufficient for pigs weighing 300 to 400 lb. Pigs should be fasted for 20 to 24 hours prior to treatment and should not be fed or watered for 3 hours after treatment. Oil of chenopodium should not be administered to animals suffering from fever, constipation, internal catarrh, or necrotic enteritis, and the treatment should not bo given to young animals or to pregnant sows. It is important 'to remember. that the ascarid that occurs in human beings is closely related to, if not identical with, the pig roundworm. In persons this parasite undergoes migrations similar to those in the pig. While it has not yet been established conclusively that the pig roundworm will develop in the human intestine, it lias been proved definitely that the larvae of'pig roundworm will migrate to the lungs of human beings and produce serious damage. Children, in particular, are likely to “pick up” ascarid eggs while playing. in areas to which pigs hayo access, especially through putting soiled fingers in the mouth, or eating fruit that may have fallen on the ground. A strict adherence to a thorough sanitation system of pig husbandry involves the keeping of pigs on well-fenced pastures. This precaution is a human health safeguard as well as sound animal husbandry practice.

THE THORN-HEADED WORM, i Thorn-lien dec\ worms arc milk white to bluish in colour and cylindrical in shape, the largest being about the size of a lead pencil. The"”head is provided with a spiny probosic (snout) by means of which the worm becomes firmly embedded in the wall of the gut. The attachment of the worm is so firm that it requires some efforts to detach one from its hold. The adult female worms produce numerous eggs which pass out with the manure. Beetle larvae (white grubs) eat the eggs along with pig manure or with ! soil contaminated with the manure of infested animals. The eggs hatch in the bodies of the grubs and develop to a stage that is infective, and the pigs obtain and swallow the grubs by rooting in soil in which they occur. The young worms escape from the bodies of the grubs as a result of the process of digestion in the pig’s stomach or intestine, or both; settle down in the intestine and develop there to egg-laying maturity.. Thorn-headed worms are decidedly injurious. Sometimes the injury is so deep that the intestine is perforated, causing peritonitis, an inflammation of the lining of the stomach, the result being usually fatal. As various drugs known to be effective in removing certain other parasites have proved ineffective in removing thorn-headed worms, control measures are the only hope at present of keeping pigs free from infestation. “Ringing” pigs tends' to keep them from rooting, and this diminishes the danger of the animals swallowing infested grubs..:—To be continued. ' . .