[Examinations on the occurrence of free-living amoebae with possible pathogenic traits in swimming pools (author's transl)].

Water of basins and filters taken from 9 indoor-pools and 5 heated outdoor-pools has been tested for free-living amoebae by means of filtration and subsequent cultivation on agar and in fluid media. In 94.6% of the samples taken from basins and in 60.7% of the samples taken from flushing back filter water, amoebae could be cultivated which all belonged to the genus of Acanthamoeba. They were tested for pathogenic symptoms by means of mouse inoculation tests, temperature tolerance tests, cross-reaction in the immunofluorescence test, and on tissue culture. 19 strains of amoebae could be re-isolated from lungs and brains of healthy mice. Only after the third series of inoculation from animal to animal, for mice characteristic pathogenic symptoms could be observed. The importance of acanthamoebae in swimming pools to the health of men cannot be estimated yet. But existing findings did not deliver reason for grave concern.