Leginella bacteria grow naturally in the environment. It can be found in most fresh and salt
water environments at temperatures ranging from about 5 – 60oC and has also been isolated
from the mud and sandy soil of river banks.
Warm water promotes its growth. It will grow in temperatures between 20 – 45oC if
nutrients from sediments and other micro-organisms are present. Laboratory tests has shown
that the survival time for Legionella decrease from hours at 50oC to minutes at 60oC and
seconds at 70oC.
Unlike other bacteria, Legionella can survive a wide range of pH values.
Legionella can be found in soil amoebac and this provides a means of dispersion and survival
in open air conditions. Water contaminated with Legionella presents a risk of Legionnaires
disease only when it is dispersed into the air as an aerosol.