PART XI. 

 INFECTIOUS DISEASES. 



CHAPTER I. 

 ACUTE GENERAL INFECTIOUS DISEASES. 



ANTHRAX. 



Definition. — Anthrax is an acute, febrile infectious disease 

 caused by the Bacterium anthracis affecting all domesticated 

 animals with the probable exception of fowls. It is character- 

 ized postmortem by splenic enlargement and serohemorrhagic 

 infiltration of the subserous and subcutaneous connective 

 tissues. 



Occurrence. — Anthrax is a disease largely confined to per- 

 manently infected districts. Generally speaking it is rare in 

 the United States, occurring only sporadically in the North, 

 although in some parts of the South, especially along the rich 

 lowlands of the lower Mississippi, it appears enzootically, 

 attacking numbers of horses and mules. The disease is more 

 common in herbivora than in either omnivora or carnivora. 

 Birds are probably never infected naturally, although the 

 disease may be with difficulty artificially transmitted. The 

 pigeon, however, forms an exception, being very susceptible 

 to infection with anthrax cultures. 



Etiology. — The Bacterium anthracis, which occurs in the 

 tissues in the form of rods and in the gastro-intestinal tract 

 and outside the body in the form of spores. The spore 

 possesses a remarkable vitality and may remain virulent for 

 months in soil, manure, foodstuffs, water, and in the blood, 

 hide, wool, or hair of animals which have died of the disease. 



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