Monday 15 July 2024
Disease Legionnaire or Disease of air conditioner


The Legionnaires' disease came to light in 1976 when an outbreak (acute febrile respiratory illness) in the American Legion in Philadelphia in the United States.

A total of 221 people infected by pneumonia, 34 of which resulted.

Investigating the causative agent of this epidemic, isolated and characterized the responsible microorganism, a Gram negative bacterium which was named legionella.

There are about 40 species of legionella and more than half can cause disease in humans. The legionella species pneumofila responsible for 90% of infections in humans.

Ideal environment for its development are water (lakes, rivers, reservoirs, pools, water supply systems of major building units, hot & hot springs). It is strong enough, can survive in various environmental conditions (temperatures from 0 to 630 C, also both in acidic and alkaline: pH from 5 to 8.5). The temperature but particularly conducive to growth and proliferation of between 40 and 500 C.

Air conditioning systems (air-condition), are no longer sources of transmission of bacteria, as previously believed.

Method of transmission

People affected by inhalation or aspiration mikrostagonidion water containing the organism. Factors facilitating the development of human disease are smoking and alcohol abuse. Also vulnerable are immunosuppressed persons and those suffering from chronic lung disease.

It is important to note that not transmitted from person to person. Can affect any age.

The incubation period ranges from 2 to 10 days.

The clinical symptoms vary and can involve several body systems.

The patient feels a few days and payment and weakness may follow a period with symptoms of influenza-like illness. Cough (initially dry then productive) may be the first symptom of lung infection. Many patients have high fever (over 390 C), symptoms of gastrointestinal (diarrhea, nausea, vomiting, stomach disorders), central nervous system (headache, confusion, lethargy, ntelirioum), the heart (bradycardia), etc. . Depending on the extent of pneumonia and the coexistence of other diseases or not, there may be shortness of breath or respiratory failure.

Laboratory findings

The chest radiograph may show: partial or lovodi pneumonia (usually unilateral and rarely bilateral), there may be pleural effusion. It can appear as lung abscess or in the form of pearls thicken if septic emboli.

The cerebrospinal fluid and the examination of faeces are sterile.

In peripheral blood we moderate leukocytosis, hyponatremia, hypophosphatemia and abnormal liver functions.

Urine present microscopic hematuria.


There are several laboratory tests for diagnosis of disease such as the indirect method anosofthorizonton antibodies (increase in antibody 1: 128), isolation of bacteria from different materials (such as sputum, bronchial secretions, blood, pleural fluid, lung tissue, etc.). It should be noted that legionella is not in the normal flora of the oropharynx and isolated from sputum or bronchial secretions is diagnostic. In addition to its cultivation requires special culture media since suspended development of the normal flora, which is why it prefers to take stock through inovronchoskopiou. Easily the diagnosis can be the detection of antigenic substances of the organism in urine.

Prognosis & Treatment

The disease legionarion is 1.8% of community acquired pneumonia. If diagnosed early, the prognosis is excellent.

The delay in diagnosis, the coexistence of other diseases, aggravating factors (smoking, alcohol abuse) or impaired defenses (eg timing of cortisone, etc.), making it difficult to deal with the disease may prolong hospitalization and complications of the disease and increase mortality, which can reach about 15%.

Drugs of choice for treatment is antibiotics such as macrolides and quinolones. The duration of treatment is about 3 weeks.

Questions - Answers