8lO MICROBIOLOGY OF DISEASES OF MAN AND DOMFSTIC ANIMALS 



affected cattle and disseminated in this way. Wider dissemination is 

 made by diseased animals moving from place to place. 



The most important considerations in controlling this disease are 

 careful disposition of contaminated manure and isolation of suspected 

 animals. The manure should be used only where it can not serve to 

 spread disease to other cattle. Sick animals should be carefully isolated 

 and premises thoroughly disinfected. 



CONTAGIOUS ABORTION OF DOMESTIC ANIMALS* 



Bacterium abortus 



The premature discharge of the products of conception from the 

 uterus is a not infrequent occurrence among domestic animals, and 

 doubtless various factors may from time to time operate in its causation. 

 Injury, excessive fermentable food, or poisonous food may at times 

 produce this result. For a long time, however, practical husbandmen 

 have recognized an epizootic form or a contagious abortion, a definite 

 transmissible disease, of which the loss of the foetus is the most promi- 

 nent characteristic. This disease appears to be generally distributed 

 in all agricultural communities. Cows, especially, are affected, but a 

 somewhat similar if not identical disease also occurs in other domestic 

 animals. 



In 1897 Bernhard Bang discovered in the uterine exudate of a cow, 

 slaughtered during an attack of this disease before the abortion had 

 occurred, a small bacterium which he was able to grow in pure culture, 

 and, by inoculating pure cultures of this organism, he produced the 

 disease in cows, sheep, goats and rabbits. 



The microbe is a short non-motile rod, staining with moderate ease, 

 and decolorized by Gram's method. It does not form spores but the 

 vegetative forms are fairly resistant to drying and may, perhaps, live 

 for some weeks under ordinary conditions in pastures and stables. Its 

 artificial culture requires special technic because of its peculiar oxygen 

 requirement. The bacterium usually fails to grow in the presence of the 

 atmospheric air or under anaerobic conditions. It requires for its de- 

 velopment a partial pressure of oxygen somewhat less than that of the 

 atmosphere. When inoculated into deep serum-gelatin-agar tubes and 

 incubated in the air, the colonies develop only in a particular zone 



* Prepared by W. J. MacNeal. 



