Legionnaire’s disease (also called legionellosis) is a pneumonia caused by bacteria. This leads to high fever and flu-like symptoms. Legionnaire’s disease is prevalent worldwide and mainly affects immunocompromised adults who are infected by contaminated water systems. With antibiotic therapy many patients can be helped. Here you can read all important information about Legionnaire’s disease.
Legionnaire’s disease: description
Legionnaire’s disease is a feverish infection caused by certain bacteria called Legionella. It leads to pneumonia with additional flu-like symptoms. Legionnaire’s disease was first diagnosed in 1976. It got its name because war veterans were infected with legionellosis at a conference in Philadelphia.
Mainly older, chronically ill people with weakened immune systems suffer from Legionnaire’s disease. Patients who receive immunosuppressive therapy, such as chemotherapy or cortisone therapy, are particularly at risk. Overall, more men than women are affected by Legionnaire’s disease, especially from the age of 50 years.
All cases of Legionnaire’s disease must be reported to the Health Department. In Germany there are about 600 reported illnesses every year. However, it is assumed that the number of unreported cases is significantly higher, as not every Legionnaire’s disease is recognized as such. It is often confused with other and much more common forms of pneumonia – only up to five percent of all pneumonia makes up the legionellosis.
The Legionnaire’s disease is spread worldwide and appears either as a single case of illness (sporadic), or it infected several people simultaneously (epidemic).
Legionnaire’s disease: symptoms
Legionnaire’s disease begins after an incubation period of two to ten days. This corresponds to the time between the infection with the bacteria and the onset of symptoms. Important legionnaires’ disease symptoms are high fever, which can quickly rise to 40 ° C and chills. In addition, a so-called atypical pneumonia develops. This is often accompanied by dry, unproductive coughing. In addition, the patients have a lung or laryngitis and cold, limb and muscle pain. Typical for a legionellosis are also complaints in the gastrointestinal tract. These include nausea and diarrhea. Some patients with Legionnaire’s disease develop encephalitis, which is associated with confusion.
To distinguish from Legionnaire’s disease is that Pontiac feverthat is triggered by the same bacteria. In contrast to Legionnaire’s disease, only flu-like symptoms without pneumonia occur in Pontiac fever. The incubation period is only one to three days, and the infection is altogether more harmless than in Legionnaires’ disease.
Legionnaire’s disease: causes and risk factors
Legionnaire’s disease is caused by infection with certain bacteria, the Legionella. These are distributed worldwide and live in warm fresh water, drinking water systems, air conditioners and humidifiers. They multiply within single cell organisms at water temperatures between 20 and 55 ° C. People get infected with the pathogens of Legionnaires’ disease when they inhale water vapor that contains the bacteria. This happens, for example, while showering. A human-to-human transmission is unknown.
In particular, patients who suffer from a chronic illness or whose immune system is weakened are particularly at risk of becoming infected with Legionnaire’s disease. The same applies to patients who receive chemotherapy or cortisone therapy and whose body’s defenses are weakened. Diabetes, alcohol and smoking are also risk factors for Legionnaire’s disease.
Legionnaire’s disease: examinations and diagnosis
The medical history (anamnesis) is important for the diagnosis of Legionnaires’ disease. Your doctor will ask you if you have any recent pneumonia, if you have recently stayed in a hotel. If so, it may indicate a Legionnaire’s disease. Even if other people in your area are affected, this may be a legionnaire’s disease. After the interview, the doctor will examine you physically. Among other things, he listens to the lungs and looks into your mouth and throat.
Anamnesis and physical examination do not allow a clear conclusion on the pathogen of the disease. Therefore, a pathogen detection must be done. Of these, urine, blood and respiratory tract secretions can be used. Legionnaire’s disease is best diagnosed by detecting Legionella in urine. Already 24 hours after the infection this is positive.
Antibodies to Legionella can only be detected in a blood sample after up to two weeks. In the acute diagnosis of Legionnaires’ disease, therefore, this study has no meaning. The cultivation of the pathogen (bacterial culture) from blood or tissue samples of the lung also takes several days.
Legionnaire’s disease: treatment
Legionnaire’s disease has to be treated with antibiotics. Macrolides, such as azithromycin, help the most. Also fluoroquinolones such as levofloxacin are well-received. The antibiotic therapy of Legionnaire’s disease lasts three weeks and should be started as early as possible. As a result, life-threatening complications can usually be avoided.
To treat the flu-like symptoms such as fever and body aches, offer painkillers such as paracetamol.
The Pontiac fever, which is associated with no pneumonia, usually heals without antibiotic therapy.
Legionnaire’s disease: prevention
You can prevent a Legionnaires’ disease by protecting yourself from the pathogens. Since the Legionella are in warm fresh water and multiply, hot water systems must be regularly maintained. They multiply at water temperatures of 20 to 55 ° C, especially when the water is not in motion. Below 20 ° C they do not multiply and only from a temperature of 60 ° C they die. In addition, Legionella are sensitive to chlorine.
- Air conditioners should be regularly maintained and cleaned.
- In hotels, before using the shower for the first time, let it run hot for a few minutes. Leave the bath in order not to breathe in the bacteria via the water vapor.
- Inhalers and humidifiers should be cleaned regularly and stored dry if not used for a long time.
This advice will help you to get ahead of the Legionnaires’ disease to protect.
Legionnaire’s disease: disease course and prognosis
General condition of the patient, disease stage at the time of diagnosis – several factors influence the course and prognosis of Legionnaires’ disease. Mortality depends on the patient’s state of health before infection. Before completely healthy people die in up to ten percent of the cases. However, in patients who previously had heart or lung disease, legionellosis is fatal in 80 percent of cases.
The Pontiac fever has a good prognosis. So far, no deaths from this type of Legionella infection are known.
A Legionella infection leaves no lasting immunity. The antibodies that form during the disease disappear over time. Therefore, it is possible to get infected with Legionnaire’s disease again.