It has been shown for the first time that Coxsackie B-3 virus will infect hibernating mammals such as the ground squirrel and the bat, in both the hibernating and nonhibernating states. Pathological changes in the heart and brown fat of squirrels in hibernation were comparable with those observed in mice. In squirrels the brain appeared to be relatively resistant, although the region of the olfactory bulb was often involved. Although no lesions were observed in bats killed in hibernation, a few died with meningoencephalitis. Viraemia was observed in both species and found to be more persistent in the bat.Biochemical studies were conducted upon the normal brown fat of the different species, and it was interesting to find that whereas the morphology and lipid content (total lipid and phospholipid) of the young mouse, adult squirrel, and adult bat were very similar, the corresponding characters of adult mouse brown fat showed marked differences. The significance of the resemblance of young mouse brown fat to that found in the hibernating mammal is being assessed further in the light of the function of the brown fat and its susceptibility to Coxsackie group B virus infection.
