Adaptation of ‘B’ Virus to the Swiss Albino Mouse

SUMMARY: The ‘B’ virus (strain no. 1) of the 68th rabbit passage has been successfully transmitted to Swiss albino mice and carried through ten passages in this species by intracerebral inoculation. This virus produced symptoms of irritability and involvement of the central nervous system in these mammals. Paralysis occurred in mice from the 6th to the 10th passages. Virus-bearing material from the 10th intracerebral mouse brain passage upon being injected intradermally into unvaccinated rabbits produced paralysis but had no effect on rabbits previously immunized against ‘B’ virus.