PARASITOLOGY. i09 



fironchiai or Pulmonic Strongylosis,— infestation 



of the bronchi or lungs. 



Gastric Strongylosis,~infestation of the stout)' 

 ach. 



Intestinal Strongylosis,— infestation of the intes- 

 tines. 



Vascular Strongylosis,— infestation of the blood 

 vessels. 



Renal Strongylosis,— infestation of the kidney or 

 fat around the kidney with strongle. 



Wet seasons favor the development of the disease, 

 as moisture insures the life of the embryo outside of 

 the body of the animal. The disease is most preva- 

 lent on low-lying and swampy lands. It may be 

 spread by the ova or embryos being carried in the 

 stream of water, or by infested animals being intro- 

 duced into a herd ; the animal becomes infested 

 through contaminated food and water. It is probably 

 necessary for these worms to pass out of the host in 

 order to complete a portion of their life history. If 

 the ova or embryos fall into water or moist places 

 they may remain alive for several months, provided 

 there is no putrefaction of organic matter. At the 

 end of one week they have been noted to moult, 

 After a second moulting they apparently become 

 shriveled and remain in the skin. In this state they 

 may resist desiccation, and possibly cold tempera- 

 ture, for a long time. Upon being taken in by the 

 host they become revivified and develop into adult 

 worms. A weakened physical condition lessens the 

 animal's powers of resistance to the invasion of the 

 parasites. 



