Legionellosis represents the serious infectious disease which is characterized by the general intoxication, defeat respiratory, urinary and the central nervous system. Legionella are transferred in the aerosol way. They are steady and can extend through cooling systems and compressors, in shower cabins and pools. As a rule, legionellosis is shown by heavy pneumonia with short wind, breast pain and a mucopurulent phlegm. The diagnosis of legionellosis is established according to a bakposev of a phlegm or bronchial washouts. Treatment first of all antibacterial - antibiotics (erythromycin, rifampicin, ).
Legionellosis represents the serious infectious disease which is characterized by the general intoxication, defeat respiratory, urinary and the central nervous system.
Characteristic of the activator
The causative agent of an infection – mobile gramotritsatelny anaerobe bacterias of the sort Legionella. For the person danger is constituted 22 of the known 40 types . Bacteria emit endotoxin, and also strong . Legionella are steady in the environment, are capable to remain up to 112 days in water at a temperature of 25 °C and 150 days at 4 °C. The tank and a source of an infection are fresh-water reservoirs (mainly with the standing water) and the soil. Legionella actively breed in protozoa (for example, amoebas) at a temperature of 35-40 °C, being protected from influence of chemical disinfectants, chlorine.
In view of considerable abilities to adaptation, legionella quite often obsemenyat cooling systems, coolers, compressors, shower and pools, and also bathrooms for implementation of a balneoterapiya, installation for respiratory physiotherapeutic procedures, fountains. Often reproduction conditions in artificial constructions for are more acceptable, than in natural objects. The person is not an infection source, even the close contact with the patient does not lead to infection with legionellosis. Do not extend an infection and other animals or birds.
Legionellosis extends on the aerosol mechanism, infection occurs at inhalation of the air-to-water suspension containing bacteria. The epidemic outbreaks of legionellosis are often connected with colonization by bacteria of water cooling systems, and also - with the production cycles connected with formation of a fine aerosol. The activator can collect in conditioners, shower cabins, dissipating in air at inclusion. At implementation of construction works realization of an air and dust way of infection is possible. Infection can happen in treatment and prevention facilities when passing various procedures: vortex bathtubs, use of ultrasonic disintegrators, intubation, etc.
At people the high susceptibility to an infection is noted, its development is promoted by smoking and abuse of alcohol, and also many chronic diseases: immunodeficiency, pulmonary diseases and exchange violations. Duration of the transferring of an infection of immunity which is formed later is not known, but the disease repeatedly does not arise. Legionellosis is frequent among clients of hotels, medics and patients in geriatric or psychiatric hospitals. Elderly people get sick mainly, men are more often (more than twice).
The incubatory period differs depending on a clinical form of an infection, in general can make 2 up to 10 days. Its average duration – 4-7 days. In most cases legionellosis proceeds in the form of heavy pneumonia (it is called "a disease of legionaries"). At some patients the prodromalny period is noted – the headache, weakness, deterioration in appetite, sometimes diarrhea takes place. In other cases the disease begins sharply, with sharp rise in body temperature to high figures and increase of intoxication (a fever, headaches, mialgiya and artralgiya, perspiration).
Soon intoxication affects TsNS, block, emotional instability, nonsense, hallucinations, faints, consciousness violation is noted. Neurodysfunctions – paralyzes of glazodvigatelny muscles, , a dizartriya and an ataxy can be noted. For 3-4 day of a disease cough, originally dry, in the subsequent - with office poor mucopurulent (sometimes bloody) phlegms is found. Short wind, breast pain is characteristic (in particular in case of accession of fibrous pleurisy). At an auskultation in lungs rattles (both dry, and melkopuzyrchaty), the centers of weakening of breath, at pleurisy – noise of friction of a pleura. Perkutorno – obtusion of a sound over the struck segments and shares.
The disease proceeds hard, will respond to treatment badly. Often is complicated by ekssudativny pleurisy, abscesses, promotes development of infectious and toxic shock. Quite often progressing respiratory insufficiency becomes the indication for transfer of the patient to artificial ventilation of lungs. Cardiovascular violations are a consequence of heavy intoxication and general hypoxia in view of the developing respiratory insufficiency.
At patients arterial hypotension, violations of a rhythm is noted (bradycardia is replaced by tachycardia). At a third of patients the infection is followed by symptomatology from a gastrointestinal tract: diarrhea, belly-aches, jaundice (is followed by corresponding changes in biochemical blood test). Violations of urinary function up to a sharp renal failure can remain in the form of consequences several months. The asthenic syndrome (weakness, increased fatigue, a memory impairment) after transferring of an infection can remain several weeks.
Legionellosis can proceed in the form of a sharp alveolit. The disease also begins with the accruing intoxication and fever, dry cough is present from the first days, further becoming damp, short wind progresses. Alveoluses propotevat fibrin and erythrocytes, partitions become edematous. In cases of the long progressing current of an alveolit the centers of fibrosis of lungs quite often are formed.
One more of legionellosis forms – fever Pontiac. At the same time the infection proceeds in the form of an acute respiratory disease. Intoxication is not less heavy, than at other forms, fever reaches 40 °C, is followed by rhinitis, an inflammation of the top airways. Often is followed by vomiting and belly-ache, disorders of the central nervous activity (sleeplessness, dizzinesses, violations of consciousness and coordination). At this form duration of the period of the main clinical manifestations usually does not exceed several days, the course of an infection good-quality. After transferring of a disease for some time the general adynamy also remains.
Sometimes legionellosis proceeds in the form of the sharp fever (Fort fever Bragg) which is followed by rashes of various character (rozeolezny, petekhialny, bark - or a skarlatinopodobny ekzantema). Rash has no localization, specific to this infection, and does not leave after regress of a peeling. In exceptional cases other forms of legionellosis meet (generalized, septic, polyorgan).
The legionellosis complication by infectious and toxic shock, quite often developing at legionellezny damage of lungs is extremely dangerous. The lethality of patients in these cases can reach 20% of cases. Besides, in view of weight of a current, legionellosis can be complicated by polyorgan nedostatochnost: warm, pulmonary, kidney, hemorrhagic symptom.
Diagnosis of legionellosis
The general blood test shows a picture of a sharp nonspecific bacterial infection (neytrofilny with shift of a leykotsitarny formula to the left, the expressed increase in SOE). The general diagnostic actions (the general and biochemical blood test and urine) carry out for the purpose of observation of a condition of bodies and systems in dynamics of a disease. At legionellezny pneumonia the X-ray analysis of lungs showing focal infiltrates in lungs (share, subtotal or total pneumonia) and also symptoms of pleurisy is informative.
The activator allocate by a bakposev from a phlegm, pleural liquid, washouts from bronchial tubes, note in blood. The most specific and exact diagnostic method is the bacteriological research, but often in view of its labor input REEF and IFA are limited to serological techniques. Besides, antibodies to legionella can come to light by means of RNIF and RMA. During the sharp period of a disease allocation of an anti-gene of the activator by means of IFA and PTsR is possible.
Treatment of legionellosis
Etiotropny treatment of legionellosis consists in prescription of antibiotics of group of macroleads (erythromycin). In hard cases medicine is appointed intravenously kapelno. As legionella quite badly give in to influence of antibiotics, supplement therapy with rifampicin, the quite good effect gives application of ftorkhinolon (). The therapeutic course usually makes up to 2-3 weeks.
For the rest the complex therapeutic actions is directed to decrease in the general intoxication, correction of respiratory insufficiency, tracking and treatment of violations in work of bodies and systems. At development of life-threatening complications apply traditional measures of intensive therapy. Oxygenation is shown to patients with heavy pneumonia, at indications – transfer to artificial ventilation.
The forecast at legionellosis
About 15% of cases terminate in a lethal outcome, it is frequent it is connected with lack of timely medical care and the weakened general condition of an organism of patients. The accompanying chronic diseases, smoking, immunodeficiencies increase risk of a failure by 2-3 times. After safe transferring of legionellosis of consequences for an organism usually it is not noted, preservation in lungs of the centers of fibrosis (decrease in volume of breath) is in rare instances possible.
Prevention of legionellosis
Prevention of legionellosis consists in control over a condition of air conditioning systems and ventilation, bathrooms and shower cabins, devices for medical procedures. Disinfection methods in the relation apply as thermal (heating of water to 80 °C), and chemical (disinfectants on the basis of chlorine). Washing and cleaning of ventilating systems at the enterprises and in institutions (and also in hotels) has to be carried out at least 2 times a year. In case of identification of colonies , the system is disinfected quarterly with the subsequent epidemiological assessment of water on existence of the activator.
Now actively physical and chemical means of disinfection (ultra-violet radiation, the water enrichments by ions of silver and copper which are not containing chlorine structures) with the purpose to reduce the harm done by disinfection to ventilating and water systems take root. Specific prevention (vaccination) of legionellosis is absent now.