

UNITED STATES 



DEPARTMENT of AGRICULTURE 



DEPARTMENT CIRCULAR 338 



\r--.i 



Washington, D. C. 



May, 1925 



PARASITES AND PARASITIC 



DISEASES OF DOGS 



MAURICE C. HALL 



Zoologist, Zoological Division, Bureau of Animal Industry 



CONTENTS 



Importance of parasite control 



External parasites and parasitic skin 



diseases 



^^ Mange , 



B Canine sarcoptic mange 



V Feline sarcoptic mange 



WL Ear mange 



B Demodectic mange 



«r Chigger infestation 



Tick infestation 



Louse infestation 



„ Flea infestation 



Page 



3 



6 



6 



7 



10 



11 



13 



14 



Internal parasites and diseases due 



to them 



Roundworm infestation 



Hookworm infestation (kennel 



anemia) 



Whipworm infestation 



Tapeworm infestation 



Tongue-worm infestation 



Coccidiosis 



Page 



16 

 17 



19 



99 



23 



26 

 28 



^ IMPORTANCE OF PARASITE CONTROL 



The parasitic diseases of dogs rank in importance with the bac- 

 terial diseases. No such provisions exist for collecting statistics on 

 diseases of animals as there are for collecting statistics on diseases 

 of man, so it is not possible to make such close approximations as 

 to prevalence of disease in veterinary medicine 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 per cent, the various forms of mange are probably entitled 

 to a second position, with a group of worm infestations -Allow- 

 ing in importance. Worm infestations, especially roundworiii and 

 hookworm infestations, are especially prevalent and deadly in 

 puppyhood and most so in tropical and subtropical countries, al- 

 though 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, but only a few of the more 

 important ones can be considered here. 



The importance of these parasites is heightened by the fact that a 

 number of them are transmissible in some form to man and to live- 

 stock. 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. 



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