SULKIN AND ALLEN 



INFLUENCE OF HIBERNATION ON INFECTION AND ANTIBODY 



RESPONSE OF BIG BROWN BATS INOCULATED WITH 



JAPANESE B ENCEPHALITIS VIRUS 



Having established the susceptibility of the big brown bat (Epte- 

 sicus f. fuscus) to experimental infection with Japanese B encepha- 

 litis virus and determined the duration of the viremic phase, the 

 degree of involvement of brown adipose tissue, brain, and kidney, 

 and learned something of the antibody response of infected animals 

 held at room temperature, the influence of low temperature on this 

 infectious process could then be studied. In a study on Japanese B 

 encephalitis infection in bats during simulated hibernation, LaMotte 

 (1958) reported that viremia is suppressed in animals placed at 

 10*^ C immediately after inoculation;upontransfertoroom tempera- 

 ture after as long as 3 months in the cold, demonstrable levels of 

 virus appeared in the blood within 2 to 5 days. 



In designing our studies, we have attempted to reproduce in the 

 laboratory situations as they might occur in nature. Whenever 

 possible, experiments are planned so that the periods in which ani- 

 mals are held at low temperature in the laboratory correspond to 

 the season of natural hibernation in an effort to simulate hibernation 

 rather than merely attain a state of hypothermia (Menaker, 1962). 

 Groups of bats are placed in cold rooms at varying times following 

 virus inoculation to represent (1) animals enterir^ hibernation im- 

 mediately after becoming infected and before infection develops to 

 a demonstrable level; (2) animals entering hibernation at the peak 

 of the infectious cycle when virus is present in blood and other tis- 

 sues; and (3) animals entering hibernation while in the immune phase 

 of the infection when virus is no longer regularly demonstrable in 

 blood or other tissues and significant levels of neutralizing antibody 

 are present. Although these studies are still in progress, we have 

 analyzed sufficient data to enable us to construct a schematic dia- 

 gram which we believe to be representative of experimental infection 

 with this virus in big brown bats under the various environmental 

 conditions described (Fig. 3), 



The uppermost section in Figure 3 depicts infection and antibody 



384 



