PARASITES AND PARASITIC DISEASES OF SWINE 
5 
uncontaminated (temporary) pasture or in a yard or yards where 
no hogs have been during the last year or on ground that has been 
plowed since hogs were there. If pastures are used for hogs the 
kidney- worm -control plan (p. 8) should be adopted. These sani- 
tary measures cannot be depended on as a preventive of hog cholera, 
and immunization should be carried on in accordance with the 
approved methods of hog-cholera control. 
TREATMENT FOR PARASITES 
Preventive measures are more important in controlling the in- 
terna] parasites of pigs than the administration of anthelmintics. 
There is only one >pe<-ies (ascarid) for which an efficient vermifuge 
is known, and this worm is of minor importance. Capsules should he. 
Used with caution on swine as they often lodge in the pharyngeal 
pouches and the contents may cause inflammation of the neck, swell- 
ing, and suffocation. Also the pig has a comparatively narrow 
throat, and liquids must be given -lowly and carefully. Worm treat- 
ments to be given in feed or a> mineral mixtures are not satisfactory. 
Drug- for pigs are bc-t administered by a competent veterinarian. 
INTERNAL PARASITES 
• 
The internal parasito <on>i>t of protozoa, flukes, tapeworm larvae, 
and roundworms. As a group the roundworm- are usually more 1 im- 
portant than the others. Several of the internal parasites are of 
special importance because they may be transferred in some stage 
of their development to man and to other animals. Not all the so- 
called cosmopolitan sjHvies of parasites are known to occur in the 
native pig. Among those not known from Puerto Rico are the 
worms that cause the disease trichinosis and the hydatid. EcM nococ- 
cu8 grcmuloxus, both of which are transmissible to man and which 
may he fatal. 
PROTOZOA 
Intestinal disorders cause Losses and interfere with the growth 
and development, especially of pigs and young hogs. Diarrhea is 
the most common and characteristic symptom. Some of these 
troubles are brought about by improper feeding, but the majority 
apparently are caused by one or more groups of bacterial and 
parasitic infections and are due to the insanitary environment in 
which the animals live. Among the parasites associated with these 
disorders are several kinds of worms and protozoa. The intestinal 
tract of hogs is frequently infested with protozoa of one kind or 
another. Usually these are harmless forms but at times some of 
them are pathogenic. 
The most common protozoa found in swine are coccidia. These 
are microscopic round or oval organisms located in the lining mem- 
brane of the large intestine. Coccidia are frequently found in fecal 
examinations, but apparently they are usually pathogenic only to 
young pigs, causing a lack of appetite and diarrhea. Also the 
comparatively huge, motile organism, BdUmvtidm m coll. a parasite 
of man. is frequently encountered. The balantidia. either alone or 
associated with pathogenic bacteria, at times produce diarrhea with 
fatalities in young pigs. On autopsy, the large intestine teems with 
