2, CIRCULAR 338, U. S. DEPT. OF AGRICULTURE 



and livestock, including the deadly hydatid with a mortality of about 

 50 percent for human patients in cases not operated on, various other 

 tapeworms which have their larvae (bladderworms) in cattle, sheep, 

 goats, swine, reindeer, etc. , and tongueworm, with both adult and larval 

 stages occurring in man and livestock. Finally, dogs carry such para- 

 sites as fleas, which attack both man and dogs, and transmit sarcoptic 

 mange to other dogs and to man. In many cases the annoying 

 prevalence 'of fleas in houses is directly due to flea-infested dogs. 



The control of parasites in the dog is therefore necessary and 

 desirable not only for the sake of the dog but for the sake of human 

 health and the welfare of the livestock industry. This control is of 

 two sorts. One method of control is that of prophylaxis or preven- 

 tion of parasitic infestation and disease, and the other is that of 

 medicinal treatment where parasitism is actually present in the 

 absence of preventive measures or in spite of them. 



Prevention is the business and duty of the dog owner. It is largely 

 a matter of sanitation and careful supervision of the dog's habits, 

 especially his food habits. Dogs usually become infested with para- 

 sites in one of two ways: 



(1) By being in contact with infested premises or infested ani- 

 mals. Dogs transmit their fleas and lice to one ano'ther and trans- 

 mit their fleas to man and also infect the premises with flea eggs and 

 larvae, thus giving rise to adult fleas which attack the first human or 

 canine victim that comes in reach. Worm eggs pass in the feces 

 (excrement) of the dog and develop to the stage where the eggs or 

 the larval worms hatching from them will infect dogs or persons, 

 infection sometimes taking place as a result of swallowing the eggs 

 or larval worms in contaminated food or water, and sometimes as a 

 result of the larval worms burrowing through the skin when it is in 

 contact with contaminated soil. 



(2) Dogs become infested with parasites by eating raw or insuffi- 

 ciently cooked meat, neglected carcasses, discarded viscera, or raw 

 fish containing the larvae of worms. Such larval worms include the 

 bladderworms occurring in the viscera of cattle, sheep, goats, swine, 

 and rabbits. It is the duty of the owner to see that premises are kept 

 clean, that the excrement is removed frequently and thoroughly, 

 that dogs eat only suitable and safe food, and that dogs are bathed 

 and kept clean and free from vermin of all sorts. This involves 

 supervision of the dog's habits to the extent of not allowing the 

 animal to run at large under conditions that permit it to eat what- 

 ever carcasses it may find or whatever animals it may kill. The dog 

 that eats offal at the country slaughterhouse or kills and eats rabbits 

 is practically certain to become infested with tapeworms. Slaughter- 

 house offal is probably the most important source of infestation of 

 dogs with hydatid tapeworm, a menace ahke to the owner of the dog, 

 his family, and his livestock. The neglected dog running at large 

 collects fleas and lice and contracts mange to an extent not possible 

 to the dog that is properly cared for and supervised. 



Medicinal treatment is the business of the veterinarian, not of the 

 dog or cat owner. _ It iavolves an accurate diagnosis, a matter that 

 calls for special trainiug, medical skill, and adequate experience, things 

 which the dog or cat owner is not likely to possess. Errors in diag- 

 nosis rnean misdirected efforts, with the possibility of injury to the 

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



