Chlamydia Trachomatis Seroprevalence Atlas of Finland 1983-2003

Objectives: To study Chlamydia trachomatis seroprevalence trends and geographical distribution over time in Finland.

Materials And Methods: First pregnancy serum samples were retrieved from the Finnish Maternity Cohort serum bank for the subcohort of 8000 women stratified by calendar years (1983-1989, 1990-1996, 1997-2003) and age at time of sample withdrawal (14-22 and 23-28 years). C trachomatis antibodies were determined using standard major outer membrane protein peptide ELISA. The spatiotemporal variation of C trachomatis seroprevalence rates was visualised by a series of maps.

Results: A decreasing C trachomatis seroprevalence trend from 1983 to 2003 was seen for both women under 23 years of age (20.8% to 10.6%) and 23-28-year-old women (19.1% to 12.5%). Constant clusters were seen around the largest cities and in eastern Finland although seroprevalence rates were generally decreasing throughout the country.

Conclusions: Only a few population-based serological studies have been undertaken on C trachomatis epidemiology over time. In Finland the seroprevalence of C trachomatis is decreasing all over the country, albeit with small clusters remaining.