Grant: Alliance Grants

Legionnaires' disease is a severe pneumonia caused by Legionella pneumophila (Lp). Cooling towers are the main source of L. pneumophila during large outbreaks. Recent deadly outbreaks have forced government to introduce regulations to improve monitoring and management of cooling towers. In spite of this action, the number of cases has continued to increase. It is currently unclear what are the best detection methods and management strategies to reduce the risk of Legionnaires' disease. The main objective of the proposed research project is to identify and validate cost effective control strategies for each step of cooling towers' life cycle (design, start-up, operation, wintering) in order to limit growth of L. pneumophila and reduce the risk of exposure while reducing the costs and environmental impacts. A combination of data mining, laboratory, bench-scale and industrial investigations in collaboration with key public and private partners will identify monitoring and treatment solutions that strike a balance between the economic burden on the cooling tower owners and the risk to public health. The relationship between the levels of Legionella spp. and L. pneumophila and the other microorganisms present together with the water characteristics will also be studied. Model systems will be used to study the efficiency of different chemical treatments and novel biological strategies to control L. pneumophila in the water and in the biofilm. The new insight on why and how a treatment is efficient will ensure a cost-effective and sustainable control of the risk of legionellosis from cooling towers. The potential health benefits of various control solutions will then be evaluated using a risk analysis and weighted against their cost and feasibility. A dependable strategy to design, monitor, operate, and treat cooling towers aimed to minimize the public health risk, the environmental impact and the cost will be proposed based on the results from this research.