Affiliation: | 1.National Institute for Health and Welfare (THL),Water and Health Unit,Kuopio,Finland;2.Medivire Occupational Health Care Center,Finland;3.UPM-Kymmene Oyj,Finland;4.Statens Serum Institut,Copenhagen,Denmark;5.National Institute for Health and Welfare,Bacteriology Unit,Helsinki,Finland;6.University of Turku,Turku,Finland;7.National Institute for Health and Welfare,Epidemiologic Surveillance and Response Unit,Helsinki,Finland;8.Mehil?inen Occupational Health Care,Helsinki,Finland |