On air conditioners, the Legionnaires and their disease

On air conditioners, the Legionnaires and their disease

An international team of scientists, consisting of American, French and Israeli experts decoded the DNA of one of the most mysterious and malevolent bacteria that inhabit our planet — Legionella.

To be precise, it decoded the genome of only one of the Legionella — Legionella pneumophila, which delivered and still delivers a lot of hassle and doctors, and ordinary people, but the significance of this event is not reduced. This bacterium causing human severe pneumonia (Named yet "Legionnaires' disease", legionellosis).

Legionella are widely distributed throughout the world, is part of the natural flora of the many ponds, both natural and artificial.

The unpleasant discovery of the pathogen in the air-conditioning systems, caused a shock as the inhabitants of the many offices, and the manufacturers of air conditioners. And as a message that the legionella bacteria found in the usual warm tap water andbath-tub in salons SPA, caused a lot of noise.

What does the Legion?

The first association with the word "Legionnaire" — Ancient Rome, the legions of Julius Caesar. Second — France, the Foreign Legion. Neither the first nor the second with Legionnaires' disease has nothing to do.

The name is connected with the American Legion (The American Legion), an organization founded in 1919 and unites Americans — participants in the various wars. It is at the congress of this NGO in 1976, held in the city of Philadelphia, and broke the flash incomprehensible infection. Within a month, the disease claimed the lives of 34 of the 220 cases of delegates and was immediately given the name "Legionnaires' disease".

How do you get infected?

In order to man infected, it needs to breathe agent present in the aqueous aerosol: a shower, a stream of air from the air conditioner, variegated fountains and fountains.

Despite the fact that Legionella can be found in the sputum of cases, transmission of infection from person to person registered. But when you consider that almost every modern office is equipped with air conditioning system, the scale of the threat are beginning to look quite impressive.

The incubation period of Legionnaires' disease in an average of 5-7 days. Described a number of clinical forms of infection: it is actually disease Legionnaires, Pontiac fever, a fever "Fort Bragg. " Are not excluded other forms of diseases.

The most studied of Legionella pneumonia, a disease that is caused by ingestion of the pathogen in human lungs. Typically, disease develops very quickly. It all starts with a moderate headache and malaise, and then — after an average day — followed by a sharp rise in temperature to39-40 degrees Celsius, accompanied by a strong fever.

The most serious complication of Legionnaires' disease, which leads to the death — respiratory failure. Mortality ranges from 5 to 30 percent, and is very dependent on the age and condition of the patient prior.

Legionella literally "flies into a rage" in conditions of reduced immunity, so to be at risk are primarily middle-aged and elderly. In addition, the predisposing factors are smoking and chronic stress, which again brings to mind an office worker.

How to find and destroy?

Special problems with the treatment of Legionnaires' disease does not arise, because Legionella is sufficiently sensitive to certain antibiotics. The main thing — to start treatment promptly as pernicious bacterium did not cause extensive damage to the lungs and throughout the body.

So the basic problem — how to recognize the pathogen Legionella pneumonia, but in this study may help scientists decipher the genome of the bacterium, and the constant vigilance of physicians facing another severe pneumonia.

Office factor

Legionnaires' disease is a pronounced seasonality — the majority of outbreaks and sporadic cases have been recorded in the summer. This is not least due to the intense work of many air conditioners 'cooling'. Apart from the risk to grab a banal cold, sitting under a powerful stream of icy air in these household appliances is another danger lurking.

In the cooling system condensate accumulates, the summer sun heats it up30-35.C, and here they are — the most favorable conditions for the growth of Legionella.

But in fairness it should be noted that a similar problem arises mainly where there is an extensive centralized air conditioning system, where water is advocated for some time and is in contact with the air supplied to the air ducts. First of all, this hotel and, paradoxically, hospitals. Of such systems legionella periodically "caught" so far.

Office air conditioners operate on a different principle, of which the condensate is removed at once (and often drips directly on the heads of passing under the windows of the office of passers). Besides, the water in these systems is too low temperature, it had to be got in and reproduce legionella.

And manufacturers of air conditioners began to stir after several outbreaks of Legionnaires' disease that occurred through the fault of their equipment. In the modern system of purification and humidification built special antibacterial filters — from the fabric to the ultraviolet. Furthermore, air conditioners are fed purity control air including content on any kind of microorganisms, at least about manufacturers regularly claim loudly.

However, this does not eliminate the need to maintain these units in a clean, sometimes change the filters, and, at least occasionally, to cause the wizard for routine inspection and maintenance.

Legionella in beauty salons

The danger has crept up on the one hand, and it is connected again with a device that facilitates us life and bringing some fun. The UK Health Protection Agency has called for mandatory bacteriological checks SPA-salons. As epidemiologists found in many bath-tub contains all of the same Legionella.

Study leader Susan Surman-Lee (Susan Surman-Lee) explained that the high humidity and temperatures in the jacuzzi baths — ideal conditions for the growth of Legionella. And when the bath begins to operate, the air bubbles burst, thus filling the room needed for the infection, an aqueous aerosol, consisting of the bacteria and water.

After examining 88SPA-salons experts found bacterial contamination in 23 of them. In at least one case of legionellosis this year demonstrated that infection has occurred in the pool SPA-salon Doctors stress. Manufacturers SPA-equipment vowed to correct in the near future.


Doctors are looking for new drugs and diagnostic techniques, manufacturers are improving models of air conditioners and hot tub … In this case, humanity priblizhaetsya sure steps to a successful solution once a complex problem, which, according to a tradition, it is the very same myself and created.

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