Parasites hud Parasitic Diseases of Dogs 



13 



Fig. 10. — The sucking louse of 

 dogs, Linognatlius piUferus, 

 Female. Ventral view. En- 

 larged. F r o m Neveu-Le- 

 m a i r e , 1912. (Measure- 

 ments : Male, 1.5 milli- 

 meters long ; female, 2 milli- 

 metei-s long. ) 



infestation. AVheneA^er possible, dogs should be kept out of tick- 

 infested woods and out of contact with tick-infested stray dogs. 



LOUSE INFESTATION 



Cause. — The dog is commonly infested with two species of lice. 

 One of these is a sucking louse, the sort commonly present on mam- 

 mals, and the other a biting louse related to the bird lice. 



The sucking louse, Linognatlius pilferus (synonym; Hcematopi- 

 niis jnlife/'), is j)ale yellow, less than one-twelfth of an inch long, 

 and has a long, slender head (fig. 10), veiy 

 different from the wide, blunt head of the 

 biting louse. It may appear blue after 

 feeding on blood. 



The biting louse, Trichodectes latus (syno- 

 nym: T. canis)^ is clear yellow in. color, 

 with darker markings, smaller than the 

 sucking louse, and has a short, wide, blunt 

 head (fig. 11). 



Symptoms. — The sucking lice feed on 

 serum and blood, and the biting lice feed 

 on the scales, scurf, and superficial por- 

 tions of the skin. In either case they cause 



irritation, which may be excessive in heavy infestations. The itch- 

 ing due to their bites causes the infested animal to scratch and rub, 

 sometimes causing sores in this manner, and constitutes a drain on 

 the nervous energ}^ Long-haired dogs appear to be more suscepti- 

 ble to louse infestation than short-haired dogs, and pups and ver}^ 

 old dogs are more susceptible to infestation and suffer more from it 

 than dogs of about mature age. The biting louse shares with the 

 flea the role of intermediate host of the common double-pored tape- 

 worm (page 25), the louse becoming infested with 

 the intermediate stage of the tapeworm as a result 

 of swallowing tapeworm eggs as it feeds on the 

 contaminated skin of the dog, and the dog becoming 

 infested with the tapeworm by swallowing such in- 

 fested lice. The tapeworm sometimes occurs in man, 

 especially children, infection occuring in the same 

 manner. 



Treatment. — Lice may be destroyed by dipping 

 the dog two or, preferably, three times at intervals 

 of from 8 to 10 days in one of the coal tar creosote 

 dips, diluted as stated on the label for use on dogs. 

 Kepetition at a suitable interval is necessar3^ as these 

 dips do not destroy the eggs, and the lice hatching 

 from them must be destroyed before they in turn 

 can lay more eggs. Clipping is an aid in treatment, as it re- 

 moves many of the eggs which are attached to the hairs and 

 permits better contact and penetration h-^ the insecticide. The 

 hair clippings should be burned to destroy the lice and their eggs 

 (nits). Oils, such as castor oil, cottonseed oil, or olive oil, may be 

 used to destroy lice, the oil being left on for several hours and then 

 washed off with warm water and soap. After being oiled, a dog- 

 should be kept in a clean box to keep him from rolling in dirt. A 



25711°— 25 3 



Fig. 11 . — The 

 biting louse of 

 dogs, Tricho- 

 dectes latus. 

 Female. V e n. - 

 tral view. En- 

 larged. From 

 Neveu-Lemaire, 

 1912. (Meas- 

 urements: 

 Male, 1.4 milli- 

 meters long; 

 female, 1.5 mil- 

 limetei-s long.) 



