PREVENTION, SYMPTOMS AND TREATMENT 253 



is of importance. The disease is very fatal (70-80 per cent, mor- 

 tality in horses and cattle), but Bacelli's treatment has given some 

 wonderfully successful results. 



Trichinosis — Trichiniasis. 



This disease may attack any of the domestic animals, but 

 usually pig's. The entrance of the larvae of the parasite (Trichina 

 spiralis) in flesh into the digestive tract is the usual means of in- 

 festation, and, in swine', eating trichi'hous mice and rats, or meat 

 from' slaughter-houses containing 1 the parasites, are — as far as is 

 known — the sources of trichinosis in these ariirrials. The larvae 

 reproduce in the bOwels of the host within a week from 1 entrance, 

 and go on ovulating for six weeks. The embryos enter the blood 

 and become encapsulated in the muscles. The symptoms are not 

 marked or characteristic and a diagnosis can' only be made by 

 microscopic examination of the' muscles post mortem, so that treat- 

 ment is merely preventive/ This consists " ih ' destroying rats "and 

 mice where pigs are kept; in burning trichinous meat; and in not 

 feeding flesh to ; swine. 



Tuberculosis; 



Tuberculosis affects animals in about the following order of 

 frequency : Cattle, birds, swine, cats, goats, horses, sheep and dogs. 

 The disease is due solely to a bacillus — the B. tuberculosis. There 

 are, however, three distinct varieties or strains of the bacillus — 

 that of man, of cattle and of birds. Tuberculosis of animals is 

 mostly, due to the bovine type of bacillus, and cattle are not very 

 successfully inoculated with the human bacillus. Cats and dogs, 

 however, do most often acquire the human bacillus by living with 

 human tuberculous patients. 



Infection occurs through the digestive and respiratory tracts 

 and extends commonly by the lymphatics, sometimes by the blood 

 or by continuity, but often penetrates the part of entrance without 

 affecting it. 



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