Legionellosis or Legionnaires’ Disease
What is Legionnaires’ Disease?
Legionnaires’ disease is a type of pneumonia that was identified relatively recently. Its name comes from its discovery in 1976 after an American Legion convention in an old hotel in Philadelphia. As the Legionnaires who had attended the convention returned to their homes, many suddenly became ill. They ran high fevers and suffered flu-like symptoms that developed into pneumonia. Many of the man died within days.
What causes Legionnaires’ Disease?
After the initial outbreak, researchers found a previously unrecognized bacterium in tissue samples taken from the victims’ lungs. When the researchers studied blood samples kept from earlier outbreaks of pneumonia-like illnesses, they found that this same bacterium was responsible. In nature, this bacterium lives in lakes and streams,but it was found to be growing in the convention hotel’s central air conditioning plant, and had spread through the hotel’s air conditioning vents and plumbing. In other outbreaks, colonies of the bacteria were found in air conditioning systems and older water systems serving hotels, hospitals and other public places.
The legionella pneumophila bacterium is the primary cause of legionellosis in humans.
How is Legionnaires’ disease controlled?
Although methods of sterilizing heating and ventilating systems which harbour the bacterium have been introduced in Australia, outbreaks of Legionnaires’ disease continue to occur.
In Australia, government bodies which monitor health and safety in industry, have issued comprehensive advice about the control of Legionnaires’ disease in places of work, as well as public venues. They can shut down such places immediately and enforce steps to make heating and ventilating systems safe. They can also prosecute the owners of such places, if they are endangering employees or customers by having poorly maintained systems.
How is Legionnaires’ disease diagnosed and treated?
Blood and sputum tests are carried out to detect the bacterium. A standard antibiotic, erythomycin, will kill these organisms and in most cases will result in a cure.
What can I do myself?
The disease does not appear to spread directly from person to person, but smoking, the heavy consumption of alcohol, and reduced immune system function all appear to increase the risk of contracting the condition.
If you suddenly suffer severe, flu-like symptoms, particularly if you have recently been at a hotel, exhibition or conference centre, you might suspect Legionnaires’ disease. This is a serious condition that should not rely on selfhelp. Although aspirin, fluids and bed rest are helpful, you must have prompt medical treatment to prevent death from irreversible lung damage – a possible complication.
When should I see my doctor?
You should see your doctor immediately if you have any of the symptoms described overleaf. You may be suffering from another illness, but you may also be experiencing Legionnaires’ disease.
If you feel too ill to reach your doctor, ask a family member or friend to make you to be hospital emergency department. Flu and pneumonia, whatever their causes, become harder to fight off as we get older. For people with chronic diseases, such as diabetes, emphysema, or heart disease, they can be life-threatening.
What will the doctor do?
Your doctor will examine you closely, paying particular attention to your heart and lungs. Samples of suptum and blood will be taken for laboratory analysis. Chest x-rays will be taken, and if the problem is Legionnaires’ disease or any other pneumonia, they will show shadowing over the lungs. Tests of blood and sputum normally provide a definitive diagnosis.
The antibiotic erythromycin, which may be combined with other antibiotics in severe cases, should quickly eradicate the infection. Full recovery can be slow, and you may feel unwell for a month or two longer.
The course of Legionnaires’ disease
The flu-like symptoms appear rapidly. Coughing produces large amounts of phlegm. As the disease progresses, breathing becomes increasingly laboured. There may be confusion, disorientation and mental changes. If untreated, Legionnaires’ disease proves fatal in about 10% of cases. Prompt treatment with antibiotics reduces the danger, and most victims recover completely. Recovery may take months, especially for smokers and older people.
Is Legionnaires’ disease dangerous?
Legionnaires’ disease can be fatal within a few days, if untreated. Older people,heavy smokers and those with any chronic illness are particularly at risk; but healthy people will have a greater chance of recovering from the disease.
Symptoms of Legionellosis
- Flu-like upper respiratory infection, with fever, aches headache and pains.
- Coughing and slight or heavy phlegm production.
- Laboured or painful breathing.
- Diarrhoea, nausea and vomiting.
- Confusion, disorientation, and other mental changes.
What can I do to avoid Legionnaires’ disease?
If you work in an ageing building with central air conditioning, make sure that it is inspected regularly and that modern antiseptic systems are installed to prevent the air conditioning ducts from harbouring the Leigonnaires’ disease organism. Do not smoke, and try to avoid crowded, smoke-filled rooms if at all possible.
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