SUPPRESSIVE EFFECT OF LOW ENVIRONMENTAL 

 TEMPERATURE ON VIRAL INFECTION IN BATS^ 



S. Edward Sulkin and Rae Allen 



Department of Microbiology 



Southwestern Medical School 



Dallas 35, Texas 



ABSTKACT 



Having established the susceptibility of insectivorous bats held at 24° C to 29° C to 

 experimental infection with rabies and encephalitis viruses and determined that virus 

 particles introduced peripherally may invade and multiply in brown fat in addition 

 to other tissues, studies were extended to establish the influence of low temperature 

 on the course of these infections in these animals. Viral proliferation in interscapular 

 brown fat, an organized, bi-lobed structure believed to be present in all hibernating 

 animals, suggested that this tissue might provide a focus of infection or target organ 

 from which virus could disseminate to other tissues. In view of the function of brown 

 fat in maintaining the hibernating animal, it seemed logical to assume that virus par- 

 ticles present in this tissue would remain viable during periods of hibernation, sus- 

 tained by the same mechanism which nurtures the whole animal, and, upon arousal of 

 the animal would multiply and disseminate to other sites. This rationale has formed 

 the basis for our studies on the influence of low temperature on viral multiplication 

 in bats and the data to be presented will be drawn from the following major areas under 

 investigation: (1) The susceptibility of various species of bats maintained at 24° C to 

 29° C to experimental infection with rabies and encephalitis viruses. (2) The influence 

 of low temperature on initiation of viral infection in bats and on the course of a pre- 

 viously established infection in these animals. (3) The influence of low temperature 

 on antibody formation in bats in response to bacterial and viral antigens (some in- 

 formation relative to rates of antigen and antibody degradation in the torpid bat will 

 also be included). (4) Reference will be made to studies on the influence of low tempera- 

 ture on viral multiplication in monolayer and explant cultures of tissues of the bat 

 as compared with tissues of warm blooded animals. 



1 The original work reported herein was supported by research grants from the Caruth 

 Foundation, the National Institutes of Health, United States Public Health Service, and the 

 Commission on Viral Infections, Armed Forces Epidemiological Board, and was sup- 

 ported in part by the Office of the Surgeon General, Department of the Army. 



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