Contamination of virological tissue cultures with a species of free-living soil amoeba.

Overwhelming contamination of a continuous cell line with a free-living soil amoeba of the genus Hartmannella is reported. The significance of the finding is discussed because of recent interest shown in the role of this and related species of amoebae in disease of humans. The methods used to detect and identify the amoeba are described and some examples of the amoebae are shown by photomicrographs. The use of metronidazole to eliminate the amoeba from tissue culture is also described. This procedure has proved successful in practice although the empirical basis for it has not been confirmed by direct assay. Consequently, there is a need to test possible alternative chemical regimens.