" Reserve 



UNITED STATES 



DEPARTMENT of AGRICULTURE 



DEPARTMENT CIRCULAR 338 



Washington, D.C. 



Library 



Issued May 1925 

 June 1934 



PARASITES AND P 

 DISEASES OF D 



By Maurice C. Hall, chief, Emmett W. Price, 

 H. Wright, associate veterinarian, Zoological 

 Industry 



^Tl^ 1 v E ° 



spins' m? * 



irasitologist, and Willard 

 nsion, Bureau of Animal 



CONTENTS 



Importance of parasite control 1 



External parasites and parasitic skin diseases . 3 



Mange 3 



Chigger infestation 11 



Tick infestation 11 



Louse infestation 13 



Flea infestation 15 



Page 



Internal parasites and diseases due to them 17 



Roundworm infestation 18 



Hookworm infestation (kennel anemia)-- 20 



Whipworm infestation 24 



Heart-worm infestation 25 



Tapeworm infestation 27 



Fluke infestation 31 



Tongueworm infestation 32 



Coccidiosis 33 



Canine piroplasmosis 34 



IMPORTANCE OF PARASITE CONTROL 



The parasitic diseases of dogs and cats rank in importance with the 

 bacterial diseases affecting these animals. No such provisions exist 

 for collecting statistics on diseases of animals as there are for collect- 

 ing statistics on diseases of man, so it is not possible to make such 

 close approximations as to prevalence of disease in veterinary medi- 

 cine as in human medicine. But conceding first place to distemper, 

 that almost universal scourge of dogs with its mortality commonly 

 estimated by veterinarians at about 50 percent, the various forms of 

 mange are probably entitled to a second position, with a group of 

 worm infestations following in importance. Worm infestations, 

 especially roundworm and hookworm infestations, are especially pre- 

 valent and deadly in puppyhood and most so in tropical and subtrop- 

 ical countries, although by no means unimportant in temperate 

 zones. There are a large number of worm parasites and of external 

 parasites, such as insects and ticks, reported from dogs and cats, but 

 only a few of the more important ones are considered here. 



The importance of these parasites, especially those of dogs, is 

 heightened by the fact that a number of them are transmissible in 

 some form to man and to livestock. A number which, occur as 

 adults in the digestive tract of the dog also occur in the same form 

 and in the same place in man. In addition dogs have a number of 

 adult parasites which occur as larval or immature parasites in man 



i This circular,_as revised, includes information on parasites- affecting- eats. 

 132241°— 37 1 



