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

(Sweden, Norway and the Netherlands), while in the southern countries most of the patients have ECM (160). It has been proved that there is some difference between the Bb strains isolated in the U.S.A. and in Europe (162), and this may account for the difference in the clinical picture between the two continents. The state of medical knowledge may be a major factor in the epidemiological data. Steere was a rheumatologist who described the disease while he was looking for the origin of an arthritis epidemic. So the attention of the American physicians was drawn to the arthritis. The first cases in Europe were described by neurologists (1,2, 167), who had realized that chronic meningitis responded to penicillin treatment. ECM as well as ACA have also been known in Europe, since the early descriptions of Afzelius and Herxheimer. Very probably, neurological and dermatological manifestations overshadowed arthritis in Europe. The first recognized Hungarian Lb cases represented the wide range of Lb symptoms (71). So Hungarian physicians were informed of the main manifestations: ECM, neuroborreliosis and arthritis. Since our laboratory was the only one in Hungary where serological test was available in 1986-1989, our position was exceptional from the epidemiological point of view. Patients representing the whole spectrum of Lb have been sent to our laboratory from every region of Hungary (75). It is unique that the clinical and laboratory work has remained in one hand for a long time. The distribution of the different symptoms of Lb in Hungary was found to be halfway between the two extremes described in Europe and in the U.S.A. (11, 22, 129). Half of our patients had ECM, one-third had neuroborreliosis, but arthritis was the leading symptom in 20%. The frequency of Lyme-arthritis is especially remarkable when the complications of ECM are analysed separately: the number of arthritis cases is almost equal to the number of patients with neurological involvement. Epidemiological studies based on big populations described an age distribution similar to ours: an accumulation of cases was found in the age ranges of 5-15 and 3050 years (21, 22, 44, 107, 129, 138). Strikingly different data can be obtained when the ratio of Lb cases within the total number of tested patients is calculated. Predominance of the youngest and oldest age groups was found in this way. This phenomenon can be explained by the fact that many of the characteristic symptoms of Lb (e.g. headache, paraesthesia, arthralgia) are rarely recognized in the youngest age groups, or are thought to be a consequence of degenerative illnesses in the older ages (156). Clinical picture Erythema chronicum migrans It starts shortly after tick bite. The longest incubation time was four months in our cases, the shortest was 48 hours: this corresponds to data of the literature (6, 158). Because of the usually short incubation period, ECM is unambiguously a seasonal disease but it may occur in the winter months, too (158). A female and child