Rickettsiosis - Causes, symptoms and treatment. MF.

Rickettsiosis is a group of acute infectious diseases caused by intracellular parasites occupying an intermediate position between bacteria and viruses;with a predominant transmission mechanism of transmission and characterized by generalized vasculitis and rash, occurring against a background of febrile-intoxication syndrome.

Rickettsiosis pathogens

With bacteria, rickettsia is considered to be similar for the following reasons: cell structure is identical, have DNA and RNA, multiply by binary division and are sensitive to the action of antibiotics. Properties that combine rickettsia with viruses: capable of intracellular parasitization, poorly multiplying on artificial nutrient media and poorly colored.

There is a conditional division of rickettsia into the following groups of diseases:

• Typhus typhus( epidemic typhus, Brill's disease, endemic or rat typhus, Canadian typhus);
• Spotted spotted fever group: spotted fever of the rocky mountains, Marseilles fever, tick-borne typhus CA

• Group of zucungamushi: typhus of the jungle or Japanese river fever;
• A group of pneumothricksiosis - only Ku-fever is attributed to it;
• A group of paroxysmal rickettsiosis - only Volyn fever belongs to it.

Earlier, the term "rickettsia" united a large group of gram-negative microorganisms, usually closely associated with their arthropods, that is, the genera Rickettsia, Coxiella, Ehrlichia, Orientia, were assigned to the same order of Rickettsiales, now they are classified as Proteobacteria and different classes, but in some literature they continue to be put together because of very many properties. Bartonella, formerly called rickettsia, is now a separate group of microorganisms, since they have a significant difference from rickettsia - the ability to reproduce on artificial nutrient media. The genus of Bartonella belonged to the causative agent of Volyn fever, but on genetic and morphological grounds it was suggested to transfer it to the genus Bartonella and the family Bartonellaceae. And Ku-fever is the only representative of the species Coxiella Burnettii of this kind of rickettsia. As a result, Ku-fever and Volyn fever now occupy an intermediate position between rickettsia and bartonella.

All rickettsiosis have a common structure:

• The presence of an adhesion factor determines the ability to anchor and further colonize.
• Endotoxin-LPS( lipopolysaccharide) cell wall, it is released only after the death of the pathogen.
• Capsule-like layer that protects against phagocytosis.
• Presence of a highly toxic thermolabile protein, which is localized in a capsule-like layer.
• Has hemolytic activity, i.e., destroys red blood cells followed by their gluing and, as a consequence, a violation of the rheological properties of the blood.

Stability:

• In the external environment are not stable and quickly die;
• Destructive for them high temperatures and at 80 ° C perish after 1 minute.
• Disinfectants are also detrimental;
• Rickettsia resistant to low temperatures and drying.

Susceptibility is very high, there are no sexual and age restrictions. Rickettsiosis is a widespread disease, registered on all continents, but more often in countries with low social development. A seasonal increase in morbidity in the winter-autumn period is characteristic, but especially from January to March, due to the growing crowding of the population, a decrease in immunity and the creation of favorable temperature conditions.

Causes of infection with rickettsia

Source - sick person and rodents. The carrier is fleas, lice, ticks. Ways of infection are trans-muscular( with an insect bite), but blood transfusion and transplacental are possible.

Blood-sucking parasites - carriers of rickettsiosis

Symptoms of rickettsiosis

Symptoms of rickettsiosis-induced diseases and their treatment are similar, but there are preferential differences, which are considered in the relevant articles: typhus and Brill disease, endemic typhus( Manchurian typhus), Northern rickettsiosisAsia, Marseilles fever, Vesicle rickettsiosis, Tsutsungamushi, Volyn fever

Therapist doctor Shabanova IE