Kapronczay Károly szerk.: Orvostörténeti Közlemények 182-185. (Budapest, 2003)
TANULMÁNYOK - ARTICLES - GOSZTONYI, Georg: Stephan Környey's contribution to the study of encephalitides. (Környey István hozzájárulása az. agyhártyagyulladás kutatásához.)
trates extend from the diencephalon to the medulla oblongata. The process damages most severely the centres controlling the muscle tone and the coordination of movement, while the spinal cord is much less involved. Thus, in this disease the principle of special neurotropism is expressed as well. At the beginning of the 1950ies Kornyey's interest was directed to the tick-borne encephalitis, which was getting increasingly frequent in Central Europe. The tick-borne encephalitis is a disease closely related to the taiga encephalitis and the louping ill; infection spreads in all the three by ticks, and the agents belong to the group of arbo viruses. Környey had an opportunity to examine histologically the brains of mice infected with the strain isolated by Fornosi and Molnár in the Transdanubian region of Hungary on the one hand, and with the Gallia strain from Bohemia, on the other (Környey, 1954, 1955). He established that the virus of tick-borne encephalitis elicits a multifocal polioencephalitis, with predilectional involvement of the brain stem. Besides brain stem structures, the Purkinje cells of the cerebellum and spinal cord motoneurons, first of all those in the cervical segments, are severely damaged. Accordingly, the tick-borne encephalitis, similar to poliomyelitis, rabies and Borna disease, belongs to the group of multifocal polioencephalitides with predilectional involvement of the brain stem, in which the concept of special neurotropism is convincingly expressed (Fig. 7). These observations have led to important theoretical assessments. Until then the principle of special neurotropism had been found only in those encephalitides, in which the infectious agent spread along neural pathways, i.e., in which the agent chose already in the periphery the tissue element, to which it had a genuine affinity. Since in the tick-borne encephalitis the mode of spread of the virus is exclusively haematogenous, the enforcement of the principle of special neurotropism is independent of the pathway, by which the virus gets access to the CNS. Környey gave a detailed description of the clinical symptomatology and histological picture of tick-borne encephalitis and the subacute sclerosing panencephalitis (SSPE) in a review in Hungarian language, published in 1958 (Környey, 1958). In this same review he also gave an account on the changes of the views concerning the pathogenesis of poliomyelitis. In the 1950ies increased attention was devoted to the occurrence of poliovirus in the intestinal content and in the sewage water. Consequently, instead of the respiratory tract, rather more the intestinal tract was regarded as the portal of entry. Since, following the enteral infection, the virus could be detected in the blood and the cerebrospinal fluid, instead of the idea of the neural spread rather that of the haematogenous spread of the agent advanced into the foreground. According to Környey, however, it could hardly be doubted that the virus spread occurred along neural pathways. To decide the question, Környey performed experiments on monkeys at the beginning of the 1970ies (Környey, 1975). In these experiments Dénes Karasszon was the virological adviser and F. Tibor Mérei performed the operations 1 . In monkeys with spinal cord transsection poliovirus was inoculated into the sciatic nerve. In the majority of animals the infection did not reach the segments cranial from the level of transsection following inoculation. In a few cases, however, inflammatory infiltrations were found also cranially from the transsection level. Környey supposed that in these cases the spinal cord transsection was not complete (Környey 1975, 1 Dr. Denes Karasszon, personal communication.
