The name of the disease comes from a meeting of former U.S. professional soldiers (American Legion) in Philadelphia in 1976, where several participants fell ill with an atypical pneumonia that could not be successfully treated with penicillin. It was not until about half a year later, in 1977, that the causative agent of this mysterious disease was diagnosed: It was the bacterium Legionella pneumophila.
Rod-shaped bacteria cause the disease
This severe pneumonia, caused by Legionella pneumophila infection, can be fatal. Legionella bacteria are found everywhere in fresh water, but not in the ocean. They are rod-shaped bacteria with small flagella with which they travel. To live and multiply in water, they require a temperature between 25 and 50 degrees Celsius; at higher temperatures, they die.
Legionella bacteria in water do not directly cause illness. However, if legionella-contaminated water is used, for example, in showers or whirlpools, the bacteria can be inhaled through the fine mist of water droplets. The disease can then occur.
The source of danger for the outbreak of Legionnaires’ disease lies in old and poorly maintained piping systems and sanitary facilities, but also in all spray and air conditioning systems.
Symptoms of Legionnaires’ disease
About two to ten days after infection, the disease breaks out with the following signs:
- Malaise
- Pain in the limbs
- Headache
- Irritative cough
Within a few hours after that, the clinical picture may then have already changed drastically: Now come high fever, chills and chest pain. Occasionally, patients also complain of abdominal pain with nausea and vomiting.
The usual pathogens are absent
The clinical picture is similar to that of strikingly severe pneumonia, without the usual pathogens of pneumonia.
In patients with compromised immune defenses, often the elderly, patients with diabetes, cancer, or HIV, for example, the disease can quickly become fatal if not detected and treated in time.
Diagnosis and therapy
Detection of Legionella is necessary to confirm the diagnosis. Antigens can be detected, for example, in urine using a fluorescence technique.
Patients with confirmed Legionella disease are treated with an antibiotic for at least ten to twelve days, and immunocompromised patients are treated for three weeks. In severe cases, patients are hospitalized.
No special precautions need to be taken when treating patients at home, as the disease is not transmitted from person to person and therefore there is no risk of infection.
Notification to the public health department
Confirmed cases of Legionnaires’ disease must be reported to the health department. Suspected disease in itself is not reportable. The respective health office then passes the data on to the Robert Koch Institute (RKI) in Berlin, among others, where they are collected and evaluated. The RKI expects up to 30,000 cases of pneumonia caused by legionella in Germany each year.
Preventive measures: Renovation of old pipelines
You can’t be vaccinated against Legionella. To prevent Legionella outbreaks, sanitary, air conditioning and spray systems must be kept free of the germs. There are a number of instructions and guidance documents issued by the Environmental Protection Agency’s Bath Water Commission for this purpose.
For example, new or planned drinking water heating and piping systems must not have water temperatures below 55 degrees Celsius at any point in the distribution system. No distinction is made between hospitals, hotels or other public buildings. However, special requirements apply to intensive care units.
The hygienic requirements to prevent legionella infestation apply just as much to dental practices and beauty salons as they do to the private sector when humidifiers or inhalers are used. These devices must be cleaned and dried regularly and thoroughly. For vacations, it is advisable to run the shower warm for a few minutes while leaving the bathroom so that the fine mist cannot be inhaled.
