14 
BULLETIN 260, IT. S. DEPARTMENT OF AGRICULTURE. 
so that neglect on the part of sheep owners is a leading reason for 
its prevalence. 
The prophylactic measures against " sheep measles n are essen- 
tially the same as those against gicl and hydatid. Diseased portions 
of slaughtered sheep and dead sheep which have not been slaughtered 
should be cooked before being fed to dogs or else disposed of so that 
dogs can not eat them. Ownerless dogs should be destroyed and other 
dogs properly fed and kept free from tapeworm. 
Muscular cysticercosis ("measles") in reindeer. — This parasite 
deserves special mention in view of the possibility that the Alaskan 
reindeer may become important in connection with the meat supply 
of this country. A large percentage of these animals, which are 
rapidly increasing in numbers, are infested with a measle parasite 
apparently the same as the form known to be the 
intermediate stage of a dog tapeworm (Tcenia 
Jerabbei). This is not only serious so far as con- 
cerns the reindeer industry, but the possibility that 
the parasite may become established in other food 
animals is not altogether excluded, though prob- 
ably remote. Tcenia krahhei occurs in Europe and 
Asia and was likely introduced with the reindeer 
or dogs imported into Alaska, though the Alaskan 
form may be a native parasite already present in 
American reindeer and carnivores before the im- 
portation of the Old World animals. 
Cysticercosis of livers and mesenteries. — Cysti- 
cercosis, or the presence of cysticerci, or bladder 
worms, in the livers, mesenteries, and omentum' or 
" fat caul," is very common in cattle, sheep, and hogs 
throughout the United States. These bladder worms. Cysticercus 
tenuicollis (fig. 8), are usually 1 or 2 inches in diameter, and the 
cyst contains a single tapeworm head. The life history follows 
the same general plan that has been outlined for the preceding tape- 
worms. When such bladder worms, or viscera containing them, are 
eaten by dogs, the head contained in each cyst passes to the intestine 
and develops a tapeworm (Tcenia hydatigena or Tcenia marc/inata) 
(fig. 9) in the dog; the eggs produced by the tapeworm pass in the 
feces of the dog onto the vegetation or into the drinking water of 
cattle, sheep, and hogs ; the eggs ingested by these animals in feeding 
or drinking release an embryo which makes its way, via the portal 
system, from the digestive tract to the liver ; in the liver the embryo 
develops into a small bladder worm (Cysticercus tenuicollis) which 
after some time slips from the liver into the body cavity and lodges 
in the omentum or mesenteries, where it attains its final growth : the 
bladder worm may then be eaten by a dog, on the death of the host 
Fig. 8. — Cysticercus 
tenuicollis, the 
thin -necked blad- 
der worm from 
the body cavity of 
cattle, sheep, 
swine, etc. Natu- 
ral size (after 
Stiles). 
