Serological surveys have been performed in two communities (Kirovsk District, Leningrad Province) endemic for
Lyme‘s borreliosis. 736 individuals (51% of the population) have been examined. Standard capillary blood samples (drops from the finger on a filter paper) have been investigated by indirect immunofluorescence. Blood sera of residents from nonendemic territories and patients with various rheumatic diseases served as a control. Serum dilution 1:80 was considered as a reliable screening titre. In general, the seroprevalence was shown to account for 9%.