BLACK-LEG 287 



Course and Prognosis. — The course of malignant edema is 

 usually rapid, death resulting from pulmonary edema in 

 twenty-four to sixty hours. The prognosis is bad, 95 per cent, 

 of the cases die. Recovery can be expected only in mild 

 infections and when proper treatment has been prompt. 



Treatment. — The treatment is surgical, and consists in 

 slitting the swellings long and deep to allow oxygen to enter 

 the tissue. A thorough disinfection of the incisions should 

 follow while subcutaneous injections of iodin tincture may be 

 made in the neighborhood of the swellings. Hot applications 

 should be avoided. 



In France, Leclaniche and Valler have practised preventive 

 inoculations with attenuated spores from edematous fluid 

 and cultures. Good results are claimed. Of scientific interest 

 is the fact that such inoculations do not immunize against 

 black-leg. 



BLACK-LEG. 



Definition. — Black-leg is an acute infectious disease of 

 young cattle, due to a specific bacillus and characterized by 

 fever and the formation of emphysematous swellings involving 

 muscular groups in various parts of the body. It is not 

 directly contagious. 



Occurrence. — While, generally speaking, black-leg has a 

 world-wide distribution, outbreaks occur usually only in 

 certain so-called black-leg districts. In this respect it re- 

 sembles anthrax, with which it was long confused. In the 

 United States the Western States suffer most, although 

 sporadic outbreaks have been observed in the Central and 

 Eastern States. The Southern Atlantic and Eastern Gulf 

 States are said to be free. In some of the Western States 

 (Kansas, Dakotas, Nebraska) the animal losses from black- 

 leg exceed those from all other diseases combined. The 

 worst infected area on this continent seems to be that 

 bounded north and east by the Missouri and Mississippi 

 Rivers and west by the Rocky Mountains, the great cattle 

 country. 



Etiology. — The Bacillus gangrsenae emphysematosa, an 

 anaerobe which occurs in soil, water, and in infected districts 



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