18 



CIRCULAR 338, U. S. DEPT. OF AGRICULTURE 



infection and to the bad effects of infestation. For parasites, as for 

 other evils, the ounce of prevention is worth the pound of cure. 

 When a pup or kitten is infested with worms it it advisable to use 

 medicinal treatment to remove them, and the more serious the 

 infestation the more urgent the need of treatment, but the younger 

 the animal and the more serious the need of treatment the more 

 dangerous is the treatment. Cats are particularly susceptible to the 

 unfavorable action of drugs and for this reason it is recommended 

 that all treatments for worms in these animals be administered by a 

 veterinarian. 



In treating dogs or cats for worms, it should be kept in mind that 

 worm remedies (anthelmintics) if potent are also dangerous, and 

 should be prescribed and administered by a competent veterinarian 

 whenever possible. Among the conditions which make drug adminis- 

 tration for worms especially dangerous are ex- 

 treme youth, age, or weakness of the patient, 

 or the presence of such debilitating diseases as 

 mange or such febrile conditions as distemper. 

 If treatment is imperative under these condi- 

 tions, diminished doses should be given at 2- 

 week intervals, removing part of the worms 

 present each time and thus protecting the pa- 

 tient. Purgation is highly important in con- 

 nection with anthelmintics. Adequate doses of 

 a suitable purgative should be given, as a rule, 

 with the anthelmintic, and if evacuation of the 

 bowels does not occur in the course of 3 or 4 

 hours, another dose of purgative should be 

 given. Enemas may also be given if it seems 

 advisable. 



ROUNDWORM INFESTATION 



Cause. — There are two species of round- 

 worms (ascarids) which commonly infest dogs, 

 and both of these occur in the United States. 

 They look very much alike and for practical 

 purposes need not be definitely identified. One 

 of these, Toxascaris leonina, is a milky white 

 worm (fig. 15) which may attain a thickness of about one-twelfth 

 inch (2 millimeters); the" male is 1.6 to 2.4 inches (5 to 6 centi- 

 meters) long, and the female is 2.4 to 5 inches (6 to 10 centi- 

 meters) or even 5.4 inches (13 centimeters) long. The internal 

 genital tubes, which can be seen^ through the body wall, do not 

 extend in the female into the anterior third of the body. This is the 

 worm most likely to be present in mature dogs. The other ascarid, 

 Toxocara canis, is pale butter yellow in color, of about the same thick- 

 ness as the preceding, but usually longer; the male is 2 to 4 inches 

 (5 to 10 centimeters) long, and the female is 2.4 to 7.2 inches (6 to 18 

 centimeters) or even 8.4 inches (21 centimeters) long. The internal 

 genital tubes extend in the female into the anterior third, and com- 

 monly into the anterior ninth, of the body. This is the worm most 

 likely to be present in pups. 



Cats, especially kittens, are sometimes infested with roundworms. 

 Two species may be encountered, one being Toxascaris leonina and 



Figure 15.— The small white 

 ascarid of dogs, Toxascaris 

 leonina. Left, male; right, 

 female. Actual size. From 

 Neveu-Lemaire, 1912. 



