692 PATHOGENIC MICROORGANISMS 



The fact that this organism cannot with regularity be distinguished from 

 the hog cholera bacillus and some other members of the paratyphoid 

 "B" group, opens the question as to whether human beings can be 

 infected by organisms derived from the disease in mice. In connection 

 with attempts at the wholesale destruction of mice by infecting bait in 

 traps with cultures, in the hope of starting an epidemic among them, 

 human infections have been reported. Troomsdorf, 28 was the first to 

 publish such cases. Meyer 29 reported an accidental laboratory infec- 

 tion from which he concluded that in man the disease could produce an 

 acute and rather severe, but short-lived disease. Shibajama 30 has 

 reported a number of cases which he carefully investigated. In all of 

 them there was definite circumstantial evidence that the individuals 

 had been exposed to infection with these organisms. In one of them 

 food had been taken from a wooden dish in which mouse typhoid bacilli 

 for the infection for bait had been kept. In another, a peasant woman 

 accidentally mixed the mouse typhoid cultures with flour. In another, 

 again, a number of people had eaten meat of a horse which had been 

 fatally infected by accidental mixture with its food of mouse typhoid 

 virus. In the last case, 34 people were infected, one of whom died. 

 The symptoms were violent gastroenteritis, coming on within twenty- 

 four hours after eating of the meat, and in many respects similar to the 

 typical disease described by Gaertner. 



B. PESTIS CAVI^E. The guinea pig disease caused by the B. Pestis 

 Cayise usually takes the form of what is commonly known as pseudo- 

 tuberculosis. It may occur epidemically in laboratory guinea pigs and 

 kill large numbers. 



DANYSZ TYPE. A definite group of the organisms, the so-called Ratin 

 or Danysz group, produce epidemic diseases among rats. By German 

 authors this Danysz group, described by the worker whose name they 

 bear in 1900, are generally regarded as very close to the true Gaertner 

 bacillus. It is pathogenic for guinea pigs and mice, and can be trans- 

 mitted to rats, as well as to these animals by feeding. There is, as in 

 all other diseases of rodents caused by these organisms, a very much 

 enlarged spleen, with inflammatory changes in the intestinal mucous 

 membrane and necrotic foci in the organs. 



The B. Abortus Equi, first described by Smith and Kilborne, has 

 been found to be the cause of infectious abortion in horses, and deserves 

 more detailed description as follows : 



28 Troomsdorf, Munch, med. Woch., 48, 1903. 



29 Meyer, Munch, med. Woch., 47, 1905. 



30 Shibajama, Munch med. Woch., 54, 1907, 979. 



