INFECTIOUS DISEASES OF MICE 455 



important features to be considered in the prevention and control of natural 

 disease in animal colonies. 



Prevention of Disease and Control of Outbreaks 



The application of general preventive measures is the only satisfactory- 

 way, in the absence of specific prophylaxis or therapeutics, to prevent the 

 introduction and spread of natural disease in a mouse colony. Success will 

 depend to a large extent upon the strictness with which the control measures 

 are maintained. "Some idea of the frequency with which spontaneous 

 disease is encountered may be gained from the figures on occurrence given in 

 the preceding sections. In addition. Greenwood and Topley (94) report 

 that during 7 years the most important spreading diseases were due to 

 Sahnonella typJiimurium. S. enteritidis, Pasteurella muricida, and Erysipelo- 

 thrix muriseptica. whereas infection due to Proteus morgani, other tj'pes 

 of Proteus, enterococci, and Corynehacterium kutscheri spread to a less 

 extent. 



It is apparent from the discussion in the last section that those procedures 

 which increase the environmental and host resistance factors and decrease 

 the microbic factor of dosage will thereby lessen the opportunity for the 

 spread of infection. Of these, the environmental factors are probably 

 most important, since they are most readily subjected to control and in 

 themselves modify host resistance and dosage. An attempt will be made 

 to present a description of the ideal physical equipment for the animal rooms, 

 although experience has shown that departures from this in many respects 

 can be made satisfactorily. The cleaning technique is modeled on that now 

 in use in the Jackson Memorial Laboratory. 



The animal rooms should be rodent proof, light, well ventilated with 

 regulation of temperature and humidity, and so constructed as to permit 

 washing of the walls and floor. This process is facilitated by a central 

 drain and a rounded baseboard which obliterates the angle between the 

 walls and the floor. The floor should be considered to be contaminated at 

 all times and nothing placed thereon should be permitted to come in con- 

 tact with cages, racks, tables, or other equipment of the room without 

 sterilization. Low tables can be used to support clean cages during actual 

 replacement of cages. Racks should be of simple metal construction set 

 out from the walls to eliminate breeding places for vermin, and if possible 

 suspended from the ceiling. They should be sufficiently spacious to permit 

 arrangement of individual cages without contact between them. The cages 



