358 BIOLOGY OF THE LABORATORY MOUSE 



Prevention and Control of Protozoan Infections 



When dealing with laboratory mice, prevention and control measures are 

 of much greater importance than treatment of protozoan infections, since the 

 life span of the mouse is so short and new animals can be so quickly produced. 

 However, there is no reason that some of the treatments recommended for 

 the different protozoan diseases of higher animals could not be employed 

 with some success providing they were regulated to suit the smaller 

 animal. 



With most of the intestinal protozoa, infection occurs by ingesting the 

 cyst forms which have passed out of the body in the feces. Therefore, 

 control measures should be directed toward preventing the contamination of 

 the food and water. A feeding and watering arrangement such as is 

 described by Bittner in the chapter on Care and Recording is excellent for 

 this reason. There is absolutely no way in which the water can become con- 

 taminated, and there is only a slight chance of the feces coming in contact 

 with the food. It is inadvisable to feed and water laboratory mice in open 

 containers placed on the floor of the cages for such practice lends itself 

 perfectly toward the perpetuation and spread of intestinal protozoan dis- 

 eases. Mouse food should be stored in mouse-tight containers and feed 

 rooms to prevent it from being overrun by stray mice which may be infected. 

 Insect pests such as silver-fish and cockroaches may be the means by which 

 the mouse food becomes contaminated. Thus, they should be eradicated. 



General hygienic procedures in caring for the cages are essential in 

 preventing intestinal protozoan epidemics. The cages should be cleaned 

 frequently and well bedded, not only to keep the mice from trampling over 

 the fecal material, but also to keep the cages dry. Most protozoan cysts 

 require moisture to live. The use of ordinary disinfectants in cages is not 

 generally effective in destroying the cysts of various protozoa. The use of 

 live steam on the cages or the emersion of the cages in a steam bath is 

 recommended for the destruction of cystic forms. 



The above control measures would also apply to the kidney coccidium, 

 Klossiella muris. In this case infection occurs when the food and water 

 have become contaminated with the urine of the infected mouse. 



In cases in which the parasite requires an intermediate host to complete 

 its life cycle, control measures can be most effectively directed toward the 

 elimination of the intermediate host. Trypanosoma dulloni is suspected of 

 employing the flea as an intermediate host, and elimination of the flea would 

 probably be the easiest method of controfling the protozoan. 



