58 BIILLETI]Sr 1089, U. S. DEPARTMEIN'T OF AGRICULTURE. 



dered objectionable for use as food. Cooking destroys the vitality 

 of the cysts and they are then harmless to dogs. 



Taenia echinococcus'^^ is a small tapeworm, also a parasite of the 

 dog, and its intermediate form, which is commonly found in reindeer, 

 consists of watery bladders or cysts, generally occurring in the lungs. 

 The cysts are small at first, but gradually enlarge and often attain 

 the size of an orange. Echinococcus cysts persist for years and may 

 kill their host. Eeindeer obtain the cysts by swallowing the eggs 

 which are passed by dogs, and dogs obtain the tapeworm by eating 

 raw reindeer meat or viscera containing the cysts. This circle may 

 be broken by treating the dogs with worm medicines and by not 

 feeding them raw meat or offal. 



Taenia krahhei also inhabits the intestines of the dog, and its in- 

 termediate cystic form, Cysticercus krahhei^ is unfortunately very 

 common in reindeer. The cysts occur in the muscular tissues and are 

 easily seen, especially in the deep muscles of the quarters. They are 

 small egg-shaped bladders with a white spot showing in the center. 

 Meat in which the cysts are numerous is considered objectionable for 

 use as food. 



At least one herd in Alaska seems to be free from the three forms 

 of cysticerci mentioned above. This is on St. Lawrence Island. 

 "When reindeer were first introduced on the island, 1902-6, no rein- 

 deer dogs accompanied them, and since that time herd dogs have 

 never been used. This fact explains their freedom from cysts. Sled 

 dogs are in use on the island, but they do not come into contact with 

 the reindeer.^® 



Prevention of tapeworms in dogs. — In view of the fact that rein- 

 deer obtain three of their worst parasites from dogs, every effort 

 should be made on the part of reindeer owners and others to ridiioii 

 their dogs of tapeworms. Reindeer dogs are undoubtedly the worst^BK 

 offenders. In the first 25 dogs treated for tapeworms it was found^tt 

 that every one harbored the parasites. Sled dogs do not carry so 

 many worms, which is to be expected, as the diet of working dogs : 

 consists chiefly of dried salmon and other fish. Of the first 24 mala- 

 mute sled dogs which were treated only 6 passed worms. ji 



'^ Man as well as nnndeer may contract echinococcus cysts by swallowing the eggsiJtl£ 

 of the dog tapeworm. Taenia echinococcus. 



'* In an unpublished reiwrt made by E. C. Joss, veterinary insx)ector, Bureau of 

 Animal Industry, 1914, some interesting observations on cysticerci in reindeer are • 

 recorded. Joss spent a month in Alaska and made a number of post-mortem examina- 

 tions of reindeer. He found both Cysticercus tenuicolUs and C. krahhei, and also re- 

 ported Taenia echinococcuH in dogs. C. krahhei cysts were encountered in the heart 

 muscles in several cases and were also recorded in the cheek and other muscles. Joss 

 treated a number of dogs with tapeworm remedies and obtained many tapeworms, - 

 which are now in the collection of the Zoological Division. This note is made through l^f, 

 the courtesy of Dr. B. H. Ransom, of the Bureau of Animal Industry, whose advice and .. 

 assistance have been invaluable in connection with working out the parasites of reindeer. 



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