Bathing fever epidemic of unknown aetiology in Finland

Since August, 1978, an epidemic characterised by respiratory symptoms and fever spread rapidly in a restricted area near Tampere, Finland. Four months later over half of the adult population reported intermittent or constant symptoms. The most frequent symptoms were cough, dyspnoea, chills, fever, headaches, muscle pain and aching of joints. The symptoms appeared to be associated with exposure to water vapour derived from tap water. Consequently this disease, which resembled extrinsic allergic alveolitis, was given the name 'bathing fever' for lack of any prevailing diagnosis. In clinical provocation tests lung diffusion capacity usually decreased, the leucocyte count increased, and a slight rise in body temperature was observed. Despite many efforts the specific causative agent in the tap water has not been identified. Neither massive chlorination of the water nor changing the sand filter of the water-works had any significant effect on the quality of the water. Therefore the source of water supply was changed in April, 1979. The symptoms have subsequently disappeared. Present knowledge about bathing fever suggests that, though rare, it may be typical of the Scandinavian type of climate.