LECTURE XXXIV 

 SYMPTOMATIC ANTHRAX 



Symptomatic aiitlirax is also known as blacklcp', bl-ick quarter, 

 eU'. It is a fatal, infections ami enzootie disease of thrifty 

 yonngr eattle. It is ai)t to appear year after year on certain 

 pastures oi- along certain valleys. Cattle more than two years 

 of age are not usually affeetecl. Sheep and goats are subject to 

 this disease, but cases are rare. Attack and recovery gives 

 immunity. 



Cause. — A short spore-forming bacillus {Bacillus chauvoei) 

 causes this disease. This bacillus produces spores and the spores 

 are very resistant, being able to renuiin virulent in the soil for 

 years — under favorable conditions. Infection usually occurs by 

 inoculation, through the skin or mucous membrane; more com- 

 monly through the former. So far as it is known, this disease 

 is not contagions by mere association. The period of incubation 

 is short — about 3 to 5 days. Authorities are not fully agreed 

 but B. chauvoei is apparently a producer of a virulent toxin. 



Symptoms. — The symptoms are local, and general or consti- 

 tutional. 



Local symptoms. — There is usually a pronounced swelling in- 

 volving the front or liind quarter, and occasionally the loin, 

 breast or throat. It does not extend below the hock or knee. 

 This swelling is characterized by crepitation as one passes the 

 hand over it, due to an accumulation of gas in the loose sub- 

 cutaneous tissues. An incision inio the swelling reveals llie 

 presence of dark, frothy blood, with ixM-uliar acetone odor. 

 The swelling is not invariable. Some cases, especially those 

 which appear at the beginning of the outbreak and die very 

 suddenly, may not show the characteristic swelling. 



Constitutional symptoms. — The constitutional symptoms ai-e 

 usually acute, and develop rapidly. The animal is dull and 

 without appetite. It shows high fever and marked debility. 

 The constitutional symptoms may last from one to three days, 

 and the case usually terminates fatally. The fever may reach 



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