INFECTIOUS DISEASES OF MICE 



393 



(spleen, lung, blood, mediastinal lymph nodes, etc.) may be necessary. 

 Differentiation of the organism from P. pseudotuberculosis and P. pestis is 

 based on the characteristics given in Table 3, although considerable individ- 

 ual variation in reactions occurs. 



A similar disease occurrmg as a spontaneous epidemic among mice in 

 the outskirts of Astracan has been reported (67). The causative organism 

 resembled the Pastcurella morphologically, but produced acid and gas in 

 glucose, acid in lactose, mannitol, and dextrin, and failed to form indol. 

 It was highly pathogenic only for mice. 



Table 3 

 DiFFERENTi.\L Ch.\racteristics OF Pasteurella muricida, P. pseudotuberculosis, 



AXD P. pestis 



+ = Positive. 



o = Negative. 

 ± = Variable. 



* Usually positive. 

 ** Usually negative. 



Control of the disease is accomplished chiefly by general preventive 

 methods. Animals vary in their individual resistance to the disease and 

 survivors of epidemics are relatively immune (93). Although some 

 immunity can be produced by vaccination with heat- or chemically-killed 

 organisms, it is doubtful whether such a measure would be effective in 

 eliminating the disease from a stock. 



Pseudotuberculosis of rodents. — Spontaneous infection due to Pasteur- 

 ella pseudotuberculosis (B. pseudotuberculosis rodentium) occurs but rarely 

 and sporadically in the mouse (202, 195), although it is common in other 

 animals (203, 244, 176). This disease is not to be confused with pseudo- 

 tuberculosis of mice due to Corynebacterium pseudotuberculosis (see following 

 section). Mice are susceptible to experimental infection, death occurring 

 within I to 3 weeks after inoculation. The course may be rapidly fatal with 

 septicemia, or chronic with signs of enteritis. Natural infection occurs 



