Dr. Murai Éva szerk.: Parasitologia Hungarica 24. (Budapest, 1991)

Isolation of Borrelia burgdorferi from ticks Thirty-one Ixodes ricinus ticks were dissected (78). Five of them proved to be infected with Bb (Table 9). In two ticks, direct dark-field microscope examination revealed 10-12 u long spirochetes indistinguishable from our standard borrelia strains cultivated under artificial conditions. These two tick isolates could also be detected by indirect immunofluorescence test, but gave weaker reaction than the standard strain. One of the spirochete strains which could be visualized by dark-field microscope, had also been seen in the culture medium but it was then lost during the serial passages. Cultivation was successful from three other ixodes females, but only two of them (Mk5 and Mk6) grew well enough for further analysis. The third one (GyK4) was heavily contaminated. All the cultivated strains gave a strong reaction with IFA. The antigenic pattern was analysed by Western blot (Fig. 30). Both of them produced strong reaction with all the patients' sera in the characteristic 60 and 41 kDa molecular weight range. A slight difference of the antigenic pattern could be detected between the two strains. Strain Mk6 showed more bands in the 41-60 kDa region. The specific band of 32 kDa OspA gave a slight reaction only, and the 35 kDa molecular weight OspB could not be visualized. Spirochetes could not be detected in the few collected haemaphysalis ticks. DISCUSSION Epidemiology The prevalence of Lb in Hungary is impossible to determine yet. The fact that most of the patients had been seen by 4-6 doctors till the correct diagnosis was established, suggests that Lb is still underestimated in Hungary. On the other hand, twice as much patients were tested in 1989 than in the previous year yet the number of Lb cases showed only a small increase. On the whole, one-third of the 3304 patients was proved to have Lb. This proportion corresponds to the findings of the Centers for Disease Control (CDC) in U.S.A. (22). Our data are comparable with those, because we followed the case definition of the CDC (23). Lb occurs in all regions of Hungary where the vectors are abundant. The morbidity data of some areas of the U.S.A., where 1-10% of the population becomes infected in every year (45, 80,145), are probably not approached in Hungary. Ticks especially the immature forms - may hardly be noticed. It is important to note that the tick bite remains unrecognized in many cases (17, 149, 166). In spite of this, a strikingly big portion of our ECM patients (80%) noticed tick bite. Of the 231 ECM cases reported by Âsbrink (6) 38 per cent recall tick bite. It is a widespread opinion that the American Lb differs from the European one. Lyme-arthritis has not been recognized in Europe for a long time, while only a few cases of neuroborreliosis were diagnosed in the U.S.A. (22, 130). There is a significant difference in the distribution of Lb symptoms between the European countries. Half of the patients has neurological involvement in the northern part of Europe