Naegleria fowleri in cooling circuits of industrial and power plants in North Moravia.

Both nonvirulent (15 strains) and virulent (1 strain) variants of Naegleria fowleri were isolated from the cooling circuits in seven of ten examined plants in North Moravia. No amoebae were found in waters with a high salinity (electric conductivity more than 614 microseconds) and with a low content of phosphates (less than 0.37 mg . 1(-1)) and oxygen (less than 7.4 mg . 1(-1)). Other results of the physical, chemical and bacteriological examinations showed no direct bearing on the occurrence of N. fowleri.