PARASITES AND PARASITIC DISEASES OE SWINE 
9 
1 w porta not . — This is one of the more common and serious para- 
sites. A large percentage of the pigs from the dry southern coastal 
area are infested. 
Symptoms and lesions, — The worms are closely attached to the 
mucosa of the small intestine, hut examinations indicate that they 
do not have the bloodsucking tendencies and do not produce anemia 
to the extent of the common hookworms in other animals. How- 
ever, heavy infestations produce a severe catarrhal inflammation 
of the intestine, resulting in unthriftiness. 
Treatment. — Either oil of chenopodium or tetrachlorethylene is 
indicated. Oil of chenopodium is given at the dose rate of one-hall" 
to 1 fluid dram (approximately 2 to 4 cc) to a 100-pound pig pre- 
ceded or followed immediately by 2 fluid ounces .(approximately 
00 cc) of castor oil. or given in the oil. As used to destroy ascarids 
the smaller dose i^ h>< s effective hut is safer and may he repeated 
at shorter intervals. 
Tetrachlorethylene may be given at the rate of 2 1 1 » CC (about % 
fluid 'Irani) for pigs s weeks old or weighing 40 pounds. A purgative 
is not usually necessary, hut if pigs arc in poor physical condition 
localise of parasites an adequate do-e of a saline purge should he 
given with this drug. 
Swine should be fasted for I s to 24 hours before, and not fed or 
watered for 3 hours after, treatment Cor worms. 
Prevention. — Sanitation, proper manure disposal, and general 
cleanliness about yards, buildings, and feeding places used by swine 
(ire indicated. 
THORN-HEADED WO KM 
The thorn-headed worm. Macretoanthorynchus hdrudmsumu (fig. 
:L ./ ) . vat ic- in length from -J 1 •> to 14 or more inches. It occurs in the 
small intestine. The body is white, cylindrical, and gradually tapers 
toward the posterior extremity. The body has somewhat the appear- 
ance of being segmented, owing to annulations in the cuticle. The 
head has an invaginating. cylindrical proboscis which bears five rows 
of backward-projecting hooks. 
Life history. — There' are several kinds of beetles which are the inter- 
mediate hosts of this worm. Among these are the four or five 
species of white grubs (gusanos bianco-) which an 1 the larvae of the 
PhyllOphaga (Loehnosterna) beetles. Also a common water beetle, 
Tropisternus cottons, is another and apparently an important inter- 
mediate host. The ova are passed in the feces and are swallowed by 
beet Lea or their larvae. The pig becomes infested with this worm by 
eating infected beetles or grubs. The water beetle is normally very 
active but after infection with this intermediate stage, in which a 
comparatively large cyst develops in the body cavity, it becomes 
sluggish. Thus it is an easier prey for pigs which may be feeding 
on the roots of plants in marshy ground. 
Importance, — This worm is of considerable importance because of 
its abundance. Pigs on a free range are most likely to pick up this 
worm and often harbor heavy infestations. 
Si/ m ptoms a ad Ic-sions. — The presence of many thorn-headed worms 
causes considerable mechanical injury and obstruction to the intestine. 
The head of the worm is attached to and deeply embedded in the wall 
of the small intestine. The comparatively large nodules frequently 
