Progression of herpes encephalitis in rabbits following the intra-ocular injection of type I virus.

The injection of HSV type I into the vitreous body of the eye in the 18-day-old albino rabbits consistently induces herpes encephalitis with 90% survival. The longterm observations up to 64 days post-inculation indicate that HSV travels slowly by cell-to-cell infection of neuroglia. The lesions follow a defined anatomical pathway producing a progressive disease not dissimilar to the natural human disease. Semiserial (1 micron) sections show that as the infection progresses tissue repair follows. It appears that HSV does not become latent, repeated episodes of viral activity cause further damage with which the repair does not keep pace. By the sixteenth day virus particles and lesions are found in contralateral side of the chiasma, lateral geniculate body and both optic nerves, but not in the ipsilateral geniculate body. This suggests that the virus does not follow the axonal route.