CHANGES IN VASCULAR PERMEABILITY OF CENTRAL NERVOUS SYSTEM BY EXPERIMENTAL HERPES SIMPLEX AND VACCINIA VIRUS INFECTIONS

A study was made to examine the occurrence and distribution of changes in vascular permeability in viral infections of the CNS in mice. Vascular permeability was demonstrated by fluorescent microscopic tracing of intravasally introduced serum albumin labeled with Evans blue. Viruses-Herpes simplex and different strains of vaccinia-were used, which produce contrasting clinical pictures and morphological changes following intracerebral inoculation. Immunofluorescent technique was employed for the localization of viral antigen. The principal findings were as follows: Infection with neurovirulent strains of vaccinia was followed by widespread lesions of the vascular permeability with exudation of albumin in the leptomeninges and diffusion in the neuropil of the cerebral and cerebellar cortex. Unless very large doses of a non-neuroadapted vaccinia strain were injected i.c., no clinical sings of disease appeared and no changes of the vascular permeability were detected in spite of virus multiplication. Following infection with Herpes simplex, changes of the vascular permeability were seen mainly in the hippocampal regions, in areas bordering on the ventricles and in the olfactory bulbs. The significance of the increased vascular permeability for the clinical picture is discussed, as is the relationship between the oedema and the reactions of the neuroectodermal cells. © 1969 Springer-Verlag.