THE DOG AS A CAERIER OF PAEASITES AND DISEASE. 5 



and deaths. In 1911, according to Stimson,^ there were 94 fatal 

 cases in man, a decrease from the figures for 1908, which is probably 

 due largely to the fact that in 1911 there were 4,625 persons treated 

 for rabies in this country. Mohler ^ states that there are only three 

 States in the Union — Idaho, Utah, and Nevada — from which it has 

 been impossible to obtain positive information to the effect that cases 

 of rabies have been found in them. The disease has since been 

 reported from Idaho and Nevada. 



Rabies is an easily preventable disease. In the present state of our 

 knowledge as to its mode of transmission, there is no reason for its 

 continued existence. It may be prevented and in time eradicated by 

 simply muzzling dogs for a sufficient period to allow the disease to die 

 out. Such a minor restraint on the dog as muzzling was sufficient to 

 eradicate rabies from England. The first case since 1902 has just been 

 reported in the spring of 1915, and this case occurred in a dog that was 

 being held in the six months' quarantine which is enforced on all dogs 

 brought into that country to prevent the disease being reintroduced. 

 Australia and New Zealand have never had any cases of rabies, and 

 a system of quarantine and inspection is provided to prevent its intro- 

 duction. It has been practically or completely eradicated from 

 Sweden, Norway, and Denmark by rigid enforcement of muzzling 

 ordinances. 



HYDATID. 



Hydatid disease occurs in man, cattle, sheep, horses, hogs, and 

 numerous other animals. It is caused by the presence of the so- 

 called hydatid (technically known as Echinococcus polymorpJius, 

 Echinococcus granulosus, Echinococcus multilocularis, etc.) in such 

 tissues as the liver, kidney, muscles, brain, lungs, etc. The hydatid 

 is a bladder worm or larval tapeworm (fig. 2), and is characterized 

 by its thick laminated cyst wall. The original bladder frequently 

 develops daughter bladders en the inside or on the outside, and in 

 these or the original bladder there develop brood capsules containing 

 tapeworm heads. There are probably two species of hydatid, though 

 they are commonly considered a single species. The bladder worms 

 are often as large as an orange and may be as large as a child's head. 

 Growth and the formation of daughter bladders may go on for an 

 indefinite period. There have been cases in which hydatids have 

 existed in man as long as 30 years before the death of the patient 

 finally ensued. Their presence in the body causes various forms of 



1 Rabies in the United States during the year 1911. By A. M. Stimson. Public Health 

 Reports, vol. 27 (28), July 12, 1912, pp. 1098-1101. 



' Rabies or hydrophobia. By John R. Mohler. Farmers' Bulletin 449. Washington, 

 1911. 



