Legionella : Symptoms and Risks

Source: Health Canada

Symptoms of pulmonary infection and legionella

Pontiac fever is a disease that resembles the flu. Its symptoms include fever, loss of appetite, headache and muscle aches. The disease is not associated with pneumonia. In most cases, it requires no special treatment, and the patient recovered after two to five days.

legionella and health

''Legionnaires'' disease is a severe lung disease characterized by pneumonia. Among its symptoms include high fever, chills and cough, as well as fatigue, headaches, muscle pain, chest pain and loss of appetite. There is also sometimes nausea, diarrhea, or an altered mental state of the patient, including confusion and memory loss. Special tests are usually required to confirm that the disease has been caused by the bacterium Legionella.

Anyone with symptoms of ''Legionnaires'' disease should immediately consult a doctor. Many cases are successfully treated with antibiotics. From 10 to about 15% of people with the disease may die, but this varies by age and overall health and may also depend on the speed with which the person receives appropriate medical care.

Risk factors associated with legionella

Anyone can contract ''Legionnaires'' disease, but the risk of legionella disease is higher among middle-aged or older men. The following persons are also at higher risk:

  • Smokers;
  • People who abuse alcohol;
  • People with lung disease or chronic kidney disease;
  • Diabetics;
  • People whose immune system is weakened for various reasons, such as cancer or organ transplant.

No group seems more at risk of Pontiac fever.


Persons exercising certain professions, such as those involved in the maintenance of large systems of air conditioning, more likely to be exposed to the bacteria legionella. However, in case of exposure, the risk of developing a serious infection still depends on the factors mentioned above.

Reduce risks

Legionella is not a common disease, and the risk of getting it is generally very low.

The best way to reduce the risk of infection lies in a combination of good engineering practices and good policies and guidelines for infection control. Water systems should be well designed and maintained. A good combined with good maintenance design, including effective treatments will prevent water stagnation and growth of Legionella.


At home, you can reduce the risk by proper maintenance of all equipment releasing water droplets in suspension, such as shower heads, the hot tubs, whirlpools and humidifiers. Make sure to clean and disinfect these devices according to manufacturer's instructions. Setting the water heater at a sufficiently high temperature (50 ° C or more) will also prevent the growth of Legionella. However, to avoid scalding, it is important to install valves or mixer taps by a qualified plumber for the temperature of hot tap water does not exceed 49 º C.