Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

serological tests are performed only in clinically unambiguous cases, which amounts to saying that infection remains undetected in a large number of patients. To illustrate the above correlations, we prepared a figure in which the counties are ranked according to an index obtained by multiplying the hit rate of tests by the absolute number of cases (Fig. 3). It is quite clear that the number of cases manifesting themselves in atypical, influenza-like symptoms and that of patients developing a mild CNS inflammation and not referred to hospital is a multiple of the cases reported. Encephalitis may be caused by a variety of other factors. If the required laboratory tests are not performed, the origin of the disease will never be revealed. Fig. 3. Number of diagnosed cases of tick-borne encephalitis by county between 1991 and 1995. The ranking of counties has been corrected on the basis of the number of positive cases as related to the number of samples submitted for testing (hit rate). See the text for more detailed explanation. The first disease cases usually occur in April every year, though that time varies depending on the actual weather conditions. The highest incidence is recorded in June and July. The number of cases declines in August and September, then rises again in October. The decisive majority of patients belong to the 20-50 years old age group, and 70% of them are men. The fatal cases occur almost invariably in men! Besides direct transmission with the tick's saliva, infection can be transmitted also by unscalded milk freshly milked from cows, ewes or goats. PREVENTION Vaccines against TBE can be prescribed by any physician. Passive immunisation serves mainly for disease prevention after the tick bite. During passive immunisation, complete antibodies are administered into the organism. Such a preparation is FSME-Bulin (Immuno), which is prepared from the blood of humans having high antibody levels to the virus. The preparation is rather expensive. It is recommended only in exceptional cases: its administration is justified to persons who have suffered multiple tick bites in highly infected