EPIDEMIOLOGISCHE SITUATION DER FRUHSOMMERMENINGOENZEPHALITIS IN BAYERN, BADEN-WURTTEMBERG UND IN DEN NEUEN BUNDESLANDERN

The epidemiology of tick-borne encephalitis (TBE) has been investigated since 1964. Between 1964 and 1977, 149 cases of TBE were reported in the western part of Germany. Since 1977 TBE has been studied more intensively. More than 1300 cases have been collected between 1977 and 1995 (37). The geographical distribution of TBE given in figure 1 and 2 is based on clinical cases of TBE. Only those cases were included which showed positive results in serological tests, e.g., specific IgM antibodies to TBEV (anti-μ-capture ELISA) (8) and clinical symptoms, about 60% of the patients had a tick bite and remembered the geographical area of exposure. 40% of the patients had no obvious tick bite. The home-address was estimated to be the area of infection as long as a patient did not leave his home town or village within the last three weeks prior to infection. Table 1 summarizes TBE cases which occurred in the years between 1982 and 1984 and the years 1991 and 1995. From this table it becomes obvious that most cases in Germany occur in Baden-Wurttemberg and Bavaria. In the eighties more than half of the infections occurred in Bavaria. This has been changed in the nineties where more cases were observed in Baden-Wurttemberg. This change of epidemiology may be due to increased vaccination programms in Bavaria especially in high endemic areas like Passau. Outside these two states of Germany small number of cases occurred in the new states of Germany and in Hessen, Rheinland-Pfalz and Saarland (table 2). In Bavaria (fig. 1) TBE cases were found in the Danube valley and along the smaller rivers Isar, Rott, Inn, Vilz and Altmuhl. So far, no case of TBE has been observed south of Munich and Augsburg or in the Alps. In the last ten years sporadic cases have been found in the Main Valley in the northern part of Bavaria. In Baden-Wurtemberg (fig. 2) infections mainly occurred in the Black Forest around Freiburg, in the valley of the Rhine river around lake Konstanz the rivers Enns, Nagold, Neckar. The change of the frequence of infections in Bavaria and Baden-Wurttemberg indicate that vaccination in recent year probably reduced the rate of infection in Bavaria.