INTERNAL PARASITES IN WILD ANIMALS. 

 By W. REID BLAIR, D.V.S. 



THE frequency of the occurrence of parasitic diseases, par- 

 ticularly those due to nematode intestinal worms, has led 

 me to devote a considerable amount of time to the investigation of 

 the worms infesting our various animals. The fact that each para- 

 site or group often demands a different management establishes a 

 greater call for a thorough study of the subject. In order to deal 

 with parasites so as to cut off their sources of survival, and extir- 

 pate them from a locality, a fuller knowledge of their life history is 

 demanded than for simple parasiticidal medical treatment. From 

 our experience, I am led to believe that parasitic diseases are an 

 important factor in the death rate of probably all zoological col- 

 lections. This is perfectly natural. In nature a wild animal roams 

 over a considerable surface of ground, and the infection it spreads 

 is therefore widely scattered ; in a zoological garden, this infec- 

 tion, with eggs and embryos of parasitic worms passed in its drop- 

 pings, is necessarily confined to a small area : hence small ranges, 

 corrals, and cages are naturally areas of concentrated infection. 

 Therefore, the mortality of animals and birds due to parasitic 

 worms, particularly to nematodes not requiring an intermediate 

 host, will be a factor with which we shall always have to reckon. 



Considering the great fatality among young canines and felines 

 caused by worms, not alone of the greatest importance is the treat- 

 ment after their existence is obvious, but treatment for preven- 

 tion is demanded with equal urgency. Probably no known dis- 

 order to which the Canidae or Felidae are subject is so destructive 

 as intestinal worms. It has been estimated by reliable authorities 

 that at least three-fourths of the whole canine race is infected 

 more or less seriously by them. 



Among the many different species of internal parasites, some 

 are found in the liver. The cruel threadworm selects the heart 

 of its victim, death resulting suddenly in a convulsion, or it may 

 be deferred for a time, during which the animal is racked by 

 agonizing pain. In the nasal cavities, the lungs, blood and muscu- 



