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Legionellez

Table of contents
Legionellez
Clinic
Diagnosis

Legionellez — the acute infectious disease of the bacterial nature which is shown in hard cases mainly fever and pneumonia in more lungs — a respiratory syndrome. Also other clinical syndromes are described.

Etiology. The activator — Legionella. Now 7 serogroups of the activator are known. Among them L. pneumophila — a gram-negative stick 2 — 3 mm long is most studied, has flagellums and intracellular vacuoles, the optional parasite, possesses ability to breed in external environment (fresh water), with a broad range of the factors defining survival borders. The antigenic structure still is finally not studied, but existence tipo-and group-specific antigens is established. Sensitivity to disinfectants same, as well as at the majority of the bacteria which are not forming dispute.

Epidemiology. The place of natural dwelling — open reservoirs. An infection source — water of air conditioning systems of recycling type, heads of a shower, evaporating condensers, water cooling installations. A way of a transmission of infection — air. This question continues to be studied: intrahospital flashes and a case of the pathologist after the opening which died of a legionellez though its transfer from the patient is not proved to people around are described.

There are no data on real distribution of this infection now, but there are all bases to consider that it is diagnosed considerably less than meets. In many countries of the world epidemic flashes and sporadic cases are described, endemicity in distribution of this infection is noted. Seasonality (July, August and September) is characteristic of epidemic flashes, sporadic cases are registered during the whole year, but also with their maximum number during the summer period. The people occupied with earth or construction works, or living near places where they are made and also the persons which were in rooms where air conditioning systems operate get sick more often or there are other devices with the infection sources stated above, or near them. All age groups of the population are susceptible to an infection. From animals rats, the Syrian hamsters, the New Zealand rabbits and other rodents are sensitive to it. Existence of antibodies in blood sera of domestic animals and monkeys tells also about possible infection them under natural conditions. An established fact of intracellular development legionell in the amoebas living in open reservoirs and the soil. It is shown that in one amoeba there can be more than 1000 microbic cells. Favorable conditions for life and reproduction legionell are found in open warm reservoirs with blue-green seaweed, dependence of their growth on photosynthetic activity of seaweed is shown.

The pathogeny is studied. The opinion that one of leaders in a pathogeny of a legionellez is toxic operation of the activator on an organism is expressed. A syndrome of the general intoxication at the beginning of a disease, and further and nature of pathological changes in lungs testify in favor of such assumption. In view of data of histologic researches of cadaveric material the legionaries who died of an illness and results of experimental studying (the multiple centers of a necrosis in a liver, walls of vessels, lymph nodes), and also detection of the activator in various bodies, it should be noted an essential role of bacteremia in a course of a disease.

The authors studying this disease connect easier forms of an infection proceeding without damage of lungs with hit in an organism of the amoebas living in the soil and water infected with legionella. At the same time it is considered that the main effective agent is not the microbe, but products of its digestion.



 
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