530 IOWA DEPARTMENT OF AGRICULTURE 



The following is an article on the subject of anthrax by Dr. 

 Walter E. Miller, Assistant State Veterinarian : 



CHARACTERIZATION. 



Anthrax is a specific infectious disease occurring sporadically and 

 in epizootics in herbivora and omnivora, and communicable to nearly 

 all warm blooded animals, and to man. It is characterized by the pres- 

 ence in the diseased tissue and liquids of Bacterium Anthracis, by an 

 enlarged spleen, blood extravasations and by local gangrene. 



HISTORY. 



Anthrax is among the oldest of the known infectious diseases and 

 descriptions of epidemics of this plague are given by Homer, Plutarch 

 and Livy before the Christian Era. While Chabert pointed out in 1790 

 that the various forms of the malady, previously described as indepen- 

 dent affections, were all one disease, Kausch gave a good description of 

 anthrax, but denied its contagiousness. Not until 1854 did Gerlach 

 prove its contagiousness by experimental inoculation. In 1885, Pollander 

 announced the discovery of unbranched rod-shaped bodies in the blood 

 of cattle dead of anthrax. After Koch's careful description of the mor- 

 phology in 1876, came Pasteur's proof of the existence of spores in 1877. 



GEOGRAPHICAL DISTRIBUTION. 



There are very few, if any, countries where the disease has not 

 been found. Europe has probably suffered most from its ravages. How- 

 ever, Northern, Eastern and Central Africa, South American Republics, 

 England, India, Russia and Australia have frequent losses, while there 

 have been outbreaks reported from at least twenty states in America. 

 The methods of disposing of dead animals, isolation and disinfection, 

 together with preventive inoculations, have placed it in the class of rare 

 diseases, save perhaps in badly infected districts. 



ETIOLOGY. 



Anthrax is caused by a germ called Bacterium Anthracis. This organ- 

 ism is found in the diseased tissue and organs of affected animals. In 

 form it is cylindrical or rod-shaped, measuring 1-5000 to 1-2500 in length 

 and about 1-25000 inch in diameter. Outside the animal body, however, 

 these organisms form small round bodies called spores, which are very 

 resistent to the destructive agents of nature. These same bodies resist 

 heat and cold to a remarkable degree and remain alive and capable of 

 producing disease after years of drying, when finally placed in a favorable 

 medium for development. Having been introduced into a locality, it 

 tends to remain for years, causing a few losses from time to time, de- 

 pending for its extent on the conditions existing in the particular local- 

 ity. Improper disposal of carcasses and careless disregard of previously 

 infected marshy land, at once presents two sources of serious proportions. 

 Besides these dangers which are of immediate consequence to stock on 

 pastures, the infection may be carried from place to place on hides, 



