Typhoid fever is a disease known since ancient times. The term typhus was introduced by Hippocrates.
Of all the variety of bacterial diseases from the "intestinal infections" section, typhoid fever is considered a rather formidable disease, primarily because of possible complications, for the removal of which surgical intervention may be required.
This disease can be designated as acute severe anthroponosis generalized intestinal infection, characterized by involvement of the small intestine lymphatic system, lymph nodes of the mesenteria and parenchymal organs.
Typhoid fever: pathogens and causes of infection
Leading to the development of such a dangerous intestinal infection as typhoid fever, the reasons for a long time were a mystery for medicine. By typhus, until the discovery at the end of the 19th century, the causative agent of this disease was indicated by all conditions accompanied by fever.
Today, it is universally recognized that the causative agent of typhoid fever is related to the Enterobacteriacea family, namely salmonella typhi( or, as it is also called, typhoid bacillus).
The causative agent was discovered by microscopy of splenic sections, Peyer's plaques and lymph nodes of mesenteria of dead people. This was done in 1874 by the Polish explorer Bronich. Later( in 1876), N.I.Sokolov also found a small number of bacteria in the organs mentioned above. And finally, in 1880 the German scientist K. Ebert made a detailed description of this bacterium. A pure culture of typhoid bacillus in 1884 was singled out by Robert Koch's pupil G. Gaffki.
The peculiarity of this bacterium in its pathogenicity is only for humans, plus it is quite mobile due to its flagella, it is not sporo- and capsule-forming, nor is it stained Gram.
"Salmonella typhy" has a very good resistance: it can last for several months in water, ice and soil, however, it immediately perishes at boiling.
It is known that the causative agent of typhoid fever is a microorganism, optionally parasitic inside cells, and is tropen to the lymphatic tissue.
Antigenic composition of typhoid rod is formed due to thermostable O-antigen, Vi-antigen( somatic) and thermolabile H-antigen( flagellum).
Sources and routes of transmission of typhoid
The patient, convalescent and bacterial carrier are the main sources of typhoid fever. The causative agent is excreted with their feces, in part with urine. As a consequence, surrounding objects, food and water can be contaminated.
Based on this, it is possible to describe quite simply the epidemic process characterizing typhoid fever: infection is realized through the fecal-oral mechanism. In other words, the oral cavity of the person is the so-called "entrance gate" of the infection.
Typical for such infections as typhoid fever transmission routes are as follows: Salmonella can enter the human body through water, with food, and also by contact and household methods.
This disease is inherent in summer-autumn seasonality. However, sporadic typhoid fever is also possible: the reasons for this lie in bacterial isolation from bacterial carriers.
Population susceptibility to typhoid universal. Immunity after typhus persistent, persists until the end of life.
Pathogenesis of intestinal infection of typhoid
Describing the pathogenesis of typhoid fever, it will be appropriate to relate it to the main periods of the disease.
At the incubation stage, the following occurs: after oral infection, most of the salmonella perishes under the influence of acidic gastric contents, the surviving microorganisms enter the small intestine with its favorable alkaline environment. Further, the typhoid bacillus is introduced and multiplies in intestinal lymphoformations( solitary follicles, as well as Peyer's patches), which are the primary foci of infection in which the granulomatous process develops.
From the primary foci, the pathogen is disseminated into regional lymph nodes, where granulomatous inflammation and the death of Salmonella also occur.
In the initial period of the disease, the pathogenesis of typhoid is associated with unfinished bacterial phagocytosis, which results in getting into the blood - bacterial and endotoxinemia develops, causing pathogens to enter the liver, bone marrow, spleen and lymph nodes with the formation of secondary foci of granulomatousinflammation.
The period of the height of the disease is associated with the entry of the typhoid rod from the secondary foci again into the blood. At this stage, the excretion begins( mainly with feces, as well as with urine, saliva and breast milk).
In the stage of reconvalescence, the intensity of specific humoral immunity increases. The pathogenesis of typhoid is completed by the increase in the completeness of phagocytosis. However, it is possible to develop a persistent persistence of L-forms of the pathogen in macrophages, which causes the development of bacterial transport.
Symptoms and features of the disease of typhoid
The latent period( incubation) of typhoid fever lasts from a week to 25 days.
In the initial period, the symptoms accompanying typhoid fever are as follows: the patient is troubled by weakness, sleep inversion( night insomnia, daytime drowsiness), headache, fever, appetite decreases, skin pallor, lethargy and adynamia are also observed. The abdomen is moderately inflated with a blunting percussion sound in the iliac region to the right( the so-called Padalka symptom).Small bubbly crepitation and / or rumbling with minor soreness is noted in this area. By the end of the period, the liver and spleen are increasing, the temperature reaches the maximum values.
Symptoms of fever of typhus characteristic for typhoid fever are high body temperature, inhibition, pallor, as well as the appearance of a scanty roseolous rash in the chest and abdomen( which occurs on the 8-10th day of the disease).Quite rare in typhoid angina develops Dyuge( necrotic-ulcerative processes in the lymph glotopharyngeal ring).
Among the clinical manifestations can be identified features of typhoid fever. This is the so-called "typhoid tongue"( edematous, coated with a white coating, with the exception of the tip and edges, where the prints of the teeth are visible);This also includes the above mentioned Padalka symptom;development of such a status as "status of typhosis"( the patient is disoriented, deafness, hallucinations, acute infectious psychosis).
Diagnosis of infectious disease of typhoid
The main method in the diagnosis of typhoid is considered to be bacteriological research, which includes the sowing of feces, blood, urine, the contents of the 12-colon intestine on nutrient media that have bile in their composition. In this case, the absolute confirmation of the diagnosis is the isolation of the blood culture of the pathogen.
Immunological diagnosis is possible from the first days of the disease. It consists in determining the pathogen antigens. The material for the study in this case is also biological fluids. This method includes enzyme immunoassay and coagglutination reaction.
Serological diagnosis of typhoid fever is based on the study of antibody titer dynamics. The diagnosis confirms its growth at least 4 times. The method is informative from 5-6 days from the beginning of the infectious process and includes the Vidal's reaction( based on agglutination), as well as the indirect hemagglutination reaction.
In addition to these methods, epidemiologic data and clinical manifestations must also be considered.
Similar to typhoid infectious diseases should be excluded in the framework of differential diagnosis at all stages of the disease.
Treatment of typhoid fever
Treatment of typhoid fever is performed exclusively in clinics. The patient is prescribed a strict pastel regimen for the entire period of the fever plus another 7 days after restoring the body temperature to normal. As a therapeutic food used table number 4.
To etiotropic therapy refers to the use of antibacterial drugs: aminoglycosides and / or fluoroquinolones.
Pathogenetic treatment of typhoid fever is detoxification, which involves the introduction of enterosorbents, glucose, haemodeza, rheopolyglucin, and abundant drinking.
Symptomatic therapy includes vitamin therapy, the appointment of sleeping pills, sedatives, and antipyretic drugs.
In case of development of bleeding, complex haemostatic therapy is performed. With perforation of the intestine, surgical treatment is performed.
A recovered person is prescribed only after normal body temperature has been restored for at least 3 weeks. At the same time, the data on the culture of urine and feces are also oriented( it is necessary to obtain 3 negative results), as well as to the bacillus( once negative) test.
Prevention of intestinal infection of typhoid
Relative to such an infection as typhoid fever, prevention is in several important positions.
First of all, it is necessary to early detection of patients, their mandatory and speedy hospitalization.
In the focus should lead epidotevovanie and disinfection with mandatory clinical and laboratory studies of contact persons.
After discharge from the clinic of a person suffering from typhoid fever, prophylaxis is reduced to the fact that a medical observation with a weekly thermometry is established for a period of 60 days( during the following month, the thermometry is carried out every 14 days).At the same time, feces and urine are examined monthly. And finally, on the 4th month, the bile is examined and the serological examination of the blood is performed. Only with negative analyzes, dispensary observation stops.
In regions with an unfavorable epidemic setting, typhoid vaccines are used: chemical and alcohol, as well as typhoid bacteriophage, which is used for emergency prevention.