Contribution to the histology of tick-borne encephalitis.

The light microscopic changes of the first human case in which electron microscopic identification of the virus was successful, are described. They are compared with the findings accepted in the literature as characteristic of tick-borne encephalitis. Although meningeal and intracerebral infiltrations were partly connected, the process cannot be regarded as a meningoencephalitis. The choroid plexus remained free from infiltration. The discontinuous inflammatory process was severe in the cerebral cortex in the pre-central region, further in the temporal lobe, and became even more accentuated in the amygdaloid nucleus. Reduction in the number of nerve cells could be ascertained chiefly in the motor cortex. The tick-borne encephalitis belongs to the group of disseminated polioencephalitides with predilection site in the brain stem, all of them caused by ribonucleic acid viruses, irrespective of whether the virus belongs to the families of Picorna-, Toga-, or Rhabdoviruses. Within this histologically outlined group the individual entities possess distinctive traits. The significance of the anoxic-vasal factor in the process formation is displayed on the instance of some traits of the histological pictures.