IgG Seroprevalence of Lyme borreliosis in the Population of the land Islands in Finland

This is a study of people living in Aland, a group of islands in the Baltic Sea between Finland and Sweden. 500 blood donors and 3,248 health service clients who did not have Lyme borreliosis were examined for Borrelia burgdorferi IgG antibodies. The method used was an ELISA containing a selection of diagnostic antigens to a Borrelia burgdorferi PKo strain. It was found that the distribution according to sex, age and titre values was identical in the 2 groups, which were therefore treated as one. 19.7% of all the sera was positive. The prevalence in men was 23.6%, and in women 16.7%. The prevalence rises with age, the highest prevalence being seen in men (44.7%) and women (37.0%) over 70 y of age. The data show that the Aland islands are strongly endemic for Lyme borreliosis compared with international levels of infection.