While Legionnaire’s Disease has been known for many years, recent outbreaks have increased awareness of the disease, its causes and prevention strategies. According to the World Health Organization, since many countries lack appropriate methods of diagnosing the infection or sufficient surveillance systems, the rate of occurrence is unknown.
In Europe, Australia and the United States, there are about 10-15 cases detected per million population. In Canada, the average number of reported cases of Legionnaires’ disease is generally less than 100 per year. However the actual number of cases is thought to be much higher, as many people with pneumonia may not be tested for infection with Legionella.

Useful Resources from ASHRAE and Allied Associations on Reducing the Risk of Legionellosis
ASHRAE Resources
ASHRAE Standard 188-2018, Legionellosis: Risk Management for Building Water Systems
ASHRAE Guideline 12-2020, Managing the Risk of Legionellosis Associated with Building Water Systems
ASHRAE Journal article - Risk Management for Legionellosis
Articles and papers addressing legionella available in ASHRAE Bookstore
Resources Provided by CDC and other Allied Associations
Guidance from the Centers for Disease Control (CDC)
PreventLD Training - FREE

Are you involved in water safety for buildings? This completely free, online training developed by Centers for Disease Control and partners can help individuals create a water management program to reduce risk for Legionnaires’ disease. PreventLD Training aligns with industry standards like ASHRAE Standard 188-2018 to effectively managing risk for Legionella bacteria.
Preventing Legionnaires’ Disease: A Training on Legionella Water Management Programs