N. fowleri infections have been linked to warm freshwater sources. These can be naturally occurring warm waters or waters that have been artificially increased by thermal pollution. Thermal pollution is the increase or decrease of water temperature caused by human activity. Increased water temperature can drastically change the ecosystem by decreasing the levels of oxygen in the water and impacting organisms’ life cycles or food sources. N. fowleri grows well between 35^oC and 46^oC, and grows fastest at 42^oC. Most other amoeboid species do not survive at temperatures at or above 42^oC. Water temperatures of 50^oC will kill all life-cycle forms of the N. fowleri amoeba. N. fowleri exist in the cyst stage at temperatures less than 26.7^oC. Temperatures below 20^oC inhibit reproduction and temperatures below 10^oC destroys the organism. N. fowleri cannot grow in salt water. Chlorine kills all life-cycle stages of N. fowleri and is the most effective way to disinfect swimming pools.