Morphological demonstration of the virus of tick-borne encephalitis in the human brain.

A case is presented in which the fourfold increase of the HI titer during the progression of the disease, and an increase in IgM content found at the beginning of the second week of the disease confirmed the diagnosis of tick-borne encephalitis. The light microscopic changes correspond to the findings accepted as characteristic to tick-borne encephalitis. Viruses, morphologically belonging to the Flavivirus genus were found by electron microscopy in the thalamus, substantia nigra, and cerebellum of the dissected brain. This paper presents the first demonstration of the virus in a case of a human tick-borne encephalitis.