SCHMIDT 



These rather serious attempts to isolate phage disclosed that only 

 one ground squirrel out of the 44 tested was excreting a bacterial 

 virus reactive against any of the host strains used. This virus (E. 

 coli phage 42) would effectively lyse our strain 14 of E. coli. There- 

 fore, we had available a working system which had been isolated 

 from the colony, and 43 animals which were naturally free of the 

 agents involved. Accordingly, a study was made of the effect of hi- 

 bernation on the retention of this bacterial virus following artificial 

 administration in the intestinal tract of the experimental animals. 



Ten squirrels were used in this investigation. Of these, 5 were in 

 deep hibernation and 5 were active but had been in the cold room for 

 the same length of time as those in the hibernating state. The tem- 

 perature in the hibernaculum was 5^ C, as mentioned earlier. Each 

 animal was given a dose of 1 ml containing 29 x 10^ plaque forming 

 units of virus. The virus suspension was cooled to 5° C and intro- 

 duced into the stomach by means of a 2 ml syringe fitted with a 2 in, 

 length of polyethylene tubing. The tubing was easily directed down 

 the throat of the animals while they were hibernating. Ether anes- 

 thesia was used in the case of the active animals. 



Following administration of the virus, quantitative determinations 

 were made for excreted virus by collecting fresh fecal material and 

 examining it by the direct plaque method described above. After each 

 specimen was obtained, the animal was transferred to a clean cage, 

 in an effort to preclude contamination of subsequent specimens. 



Enteric Virus Study 



Following these investigations, attempts were made to determine 

 the natural occurrence of enteric viruses in the animals. Thirty- 

 two squirrels were examined repeatedly over a period of 4 months 

 for the presence of enteric viruses in their intestinal contents. It 

 was surprising (justified or not) to find that all were free of viral 

 agents capable of inducing a cytopathogenic effect in monolayers of 

 either HeLa, human amnion, or monkey kidney cells. Therefore, we 

 initiated studies to determine the effect of hibernation on the reten- 

 tion of specific enteric viruses in the intestinal tract of these ani- 

 mals following artificial administration. Preliminary tests had indi- 



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