Pathogenicity. 1013 



Of other causes of pyelonephritis pure cultures have been 

 found of the bacillus pyogenes (in cows and calves [Ernst]), 

 13yogenic staphylococci (Cadeac & Morot, Ernst), streptococci 

 (Baillet & Seres, Ernst), bacillus pyocyaneus (Cadeac & Morot), 

 bacillus enteritidis (Sommer), bacilli of the colon group (Jensen, 

 Kitt). Most of the enumerated bacteria were also often found 

 together with the corynebacillus renalis, or several kinds of 

 them at the same time, so that a mixed infection was present 

 (Kitt, Ernst, Zschokke, Sommer). In two cases of kidney 

 tuberculosis Ernst found similar changes as in pyelonephritis, 

 although the tubercle bacillus was alone present. 



The ability of the bacteria of the colon group to cause pyelonephritis after 

 being introduced into the bladder was proved experimentally by Schmidt & Aschoflf, 

 Savor, V. Wiinschheim. On the other hand J. Koch produced proofs to show that 

 saprophytic staphylococci are also capable of giving rise to a typical pyelonephritis 

 in rabbits after subcutaneous or intravenous injection. 



There exists therefore no specific virus of pyelonephritis in the 

 domestic animals. Nevertheless, in consideration of what has been 

 observed, it is not possible to agree with Ernst's view, according to which 

 the Corynebacillus renalis has hardly anything to do with the genesis 

 of the disease. Earher observers and recently also Kiinnemann found 

 pure culture of the bacillus in question in the diseased kidneys, and 

 Ernst himself found it almost pure in a few cases. On the other hand, 

 certain diseases (Pseudotuberculosis of sheep, ulcerating lymphangitis, 

 pustulous dermatitis) prove that the bacteria belonging to the group of 

 the Bac. pseudotuberculosis ovis possess pathogenic properties under 

 certain conditions. 



Although it is not determined with certainty how the 

 natural infection is produced, it is at least very probable that 

 the virus may be introduced into the kidneys or into the urinary 

 organs in general in various ways. The general experience 

 that the disease develops most frequently in cows, a certain 

 time after parturition, if during the latter the birth canal had 

 been injured or the placenta had been retained or if metritis 

 developed, makes it very probable that the virus multiplies 

 promptly in the diseased genital organs and may enter the 

 urinary organs if opportunity serves. This can take place 

 the more easily as most of the enumerated pathogenic germs 

 are ubiquitous bacteria, and some of them (for instance the 

 bacteria of the colon group) are regular inhabitants of the 

 intestinal canal. 



The dissemination of the virus may also take place from 

 other organs which are diseased in some manner owing to a 

 bacterial invasion. In a case described by Ernst the trouble 

 developed in connection with an abscess in the region of the 

 xiphoid cartilage, while in a case in a young steer observed 

 by Hess the infection had probably proceeded from a para- 

 urethral abscess. In newborn animals the umbilicus appears 

 often to be the point of entrance of the bacteria, without it 



