Protozoa in Cooling Towers: Implications for Public Health and Chemical Control

Cooling towers provide ideal environments for the proliferation of micro-organisms including Legionellae. Despite increasing technical and regulatory controls on their operation and maintenance, cooling towers are commonly reported sources of Legionellosis outbreaks within Australia. The on-going potential for cooling towers to contribute to serious disease was demonstrated by the Melbourne Aquarium outbreak in 2000, where 125 cases of Legionnaires' disease and 4 deaths were reported (Greig et al. 2004). By understanding the chemical treatments required for the effective control of protozoa, informed public health strategies for the risk management of cooling towers can be further developed