Parasites and Parasitic Diseases of Dogs 3 



nosis mean misdirected efforts, with the possibiUty of injury to the 

 sick animal, loss of time and money, and the possibility that this 

 lost time will allow the real condition to go unrecognized until it is 

 too late to save the animal. Treatment also involves the use of 

 highly potent drugs, carefully selected with due regard to the end 

 to be accomplished, and administered in such doses and in such a 

 way as to cure disease without injuring the patient. The possible 

 contraindications for treatment, conditions which make it evident 

 that certain drugs or doses are dangerous, must be ascertained and 

 kept in mind. The anthelmintics (drugs used to remove worms) 

 are always poisonous, being intended to poison the worms, and must 

 be given in such doses as will accomplish that object without mate- 

 rially injuring the patient. Insecticides injudiciously applied to the 

 skin to kill parasites may injure the skin or kill the patient. In this 

 discussion of parasites a number of treatments are described, since 

 in some cases it will be necessary for an owner to treat his dogs, 

 owing to the fact that there are no competent A^eterinarians available. 

 It is understood, of course, that an owner gives such treatment at 

 his own risk and that he assumes the responsibility for his diagnosis, 

 selection of drugs, dosage, method of administration and technic, 

 and the risk of possible bad results. Each dog presents his own 

 special individual case, and no general directions can cover all of 

 the possibilities. Passing judgment on the individual case is 

 precisely where the skilled veterinarian becomes indispensable, and 

 whenever possible he should be emploj^ed. 



EXTERNAL PARASITES AND PARASITIC SKIN DISEASES 



MANGE 



The dog suffers from mange of three sorts^sarcoptic mange, 

 ear mange, and democlectic mange. Sarcoptic mange occurs over 

 the body and is characterized by the formation of crusts or scabs 

 in advanced stages of the disease. Ear mange, as the name implies, 

 occurs in the ears. Democlectic mange, also called red mange or 

 follicular mange, occurs over the body and is characterized by a 

 falling out of the hair and frequently a reddening of the skin in 

 the early stages, the condition commonly progressing to the forma- 

 tion of pustules. In this disease and in sarcoptic mange there is a 

 characteristic impleasant " mousy " odor. 



CANINE SAECOPTIC MANGE 



Cause. — Canine sarcoptic mange is due to the canine sarcoptic 

 mange mite, ScDfrcoptes scahiei canis, a form related to the spiders. 

 This mite is very small, the largest specimen being less than one- 

 fiftieth inch long. The general appearance under the microscope is 

 that shown in Figure 1. The sarcoptic mites, this form and its 

 near relatives, have very short hind legs, not projecting beyond the 

 margin of the body. AAHien a dog is suspected of having mange, 

 a portion of the diseased skin should be scraped with a dull knife and 

 the scraping examined for mites. The scraping must be deep 

 enough to draw blood, as these mites burrow deep into the skin, 

 and it may be necessary to make scrapings from several areas. The 



