Any LD infection is caused by exposure to the dangerous Legionella bacteria. This type of bacteria tends to flourish in high moisture environments, so it can be contracted in a variety of places. Those who spend time outdoors near lakes, rivers, or humid environments may end up exposed to Legionella bacteria. People who work with damp soil, such as gardeners or farmers, can contract LD through the soil. However, even those who live in urban environments can get the condition. Man made water systems, including hot tubs, air conditioning units, plumbing systems, water heaters, and decorative fountains can all harbor Legionella. In big buildings where these systems service many residents, the condition can spread rapidly.
People who come in contact with Legionella infected water can end up with LD through a variety of ways. Legionella normally does not pass from person to person, but it is passed through inhalation or consumption of the bacteria. This means that a person can get infected by drinking contaminated water, or they can get infected through tiny drops of water that they breathe in. Systems like fountains that spray a fine mist through the air can quickly spread lD.