58 BULLETIN 1089, U. S. DEPARTMENT OF AGRICULTURE. 
dered objectionable for use as food. Cooking destroys the vitality 
of the cysts and they are then harmless to dogs. 
Taenia echinococcus 15 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. Keindeer 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 krabbei also inhabits the intestines of the dog, and its in- 
termediate cystic form, Cysticercus krabbei, 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. 16 
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 rid 
their dogs of tapeworms. Reindeer dogs are undoubtedly the worst 
offenders. In the first 25 dogs treated for tapeworms it was found 
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. 
15 Man as well as reindeer may contract echinococcus cysts by swallowing the eggs 
of the dog tapeworm, Taenia echinococcus. 
16 In an unpublished report made by E. C. Joss, veterinary inspector, Bureau of 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 Cystioercus tenuicollis and C. hrabbei, and also re- 
ported Taenia echinococcus in dogs. C. krabbei 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 
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. 
