Yersiniosis and Pseudotuberculosis

What is Yersiniosis and Pseudotuberculosis?

Yersiniosis and pseudotuberculosis are acute zoonotic infectious diseases characterized by damage to the gastrointestinal tract in combination with a variety of toxic-allergic and polychagic symptoms.

The similarity of etiological characteristics, as well as pathogenesis, pathoanatomical changes, epidemiology and clinical manifestations allows to consider pseudotuberculosis and intestinal yersiniosis as intestinal infections close to each other.

Brief historical information
The causative agent of pseudotuberculosis (Yersinia pseudotuberculosis) was discovered by L. Malasse and V. Vignal (1883), the pathogen of intestinal yersiniosis (Y. enterocolitica) – D. Schleifstein and M. Coleman (1939). The bacteria were named after the Swiss bacteriologist A. Yersen, who discovered the plague pathogen (1894). All the bacteria mentioned were included in the Yersinia genus of the family Enterobacteriaceae by a decree of the International Bacteria Systematics Committee (1972).

The first cases of pseudotuberculosis in humans in the form of abscessing mesadenites were described by V. Masshof and V. Knapp (1953). In 1959, in the Far East of the USSR, an epidemic of pseudotuberculosis was observed, which was at that time called the Far Eastern scarlet-like fever. Later V.A. Znamensky and A.K. Pseudotuberculosis bacilli (1965) were isolated from the faeces of patients with scarlet fever in the Far East of scarlet fever. The etiological role of the pathogen in the occurrence of Far Eastern scarlet-like fever was proved by V.А. Znamensky in the experience of self-infection.

The first human diseases caused by Y. enterocolitica were recorded in 1962-1963. in France, Belgium, and also Sweden and other Scandinavian countries.

Causes of Yersiniosis and Pseudotuberculosis

Y. pseudotuberculosis and Y. enterocolitica are motile (peritrichs) literary optional anaerobic spore-forming sticks of the Yersinia genus of the family Enterobacteriaceae. Unpretentious to nutrient media. The optimum temperature for growth is 22-28 ° C, can also multiply within 2-40 “C, which allows to refer them to psychrophilic bacteria. In refrigerators (at 4-6 ° C) bacteria are able to persist for long and multiply on food. Very resistant to freezing and thawing, can last for a long time in soil and water. These properties are of great epidemiological importance. At the same time, Yersinia is sensitive to the effects of sunlight, drying, boiling, the action of ordinary disinfectants. Pathogenic properties of iersin and are associated with their major toxins – enterotoxin, endotoxin (LPS-complex), cytotoxins. Enterotoxin Y. enterocolitica plays a leading role in the development of severe diarrhea; enterotoxin Y. pseudotuberculosis has a lower pathogenic value. first of all, invasive activity. In particular, this circumstance is largely associated with frequent cases of generalization of the infection and the difficulty of excreting Y. pseudotuberculosis from the intestine. In contrast, in Y. enterocolitica, invasiveness, with a few exceptions (Serovar 09), is not pronounced.

Bacteria have flagellated (H-), somatic (0-) antigens, and also a virulence antigen (V- and W-) located on the outer membrane. According to the structure, Y. pseudotuberculosis O-antigen is divided into 8 serovars; most strains (60-90%) belong to the first serovar. According to the structure, the O-antigen of Y. enterocolitica secrete more than 50 serovars; most of the known isolates belong to serovars 03 (15-60%), some to 05.27 (10-50%), 07.8 (5-10%) and 09 (1-30%). The heterogeneity of the Yersinia O-antigen determines their intraspecific and common enterobacteria for antigenic associations with the plague bacillus, as well as with salmonella, brucella, shigella, cholera vibrio, proteus, hafnium. An important pathogenetic role is played by the antigenic bonds of Yersinia with certain human tissue antigens (thyroid gland, synovial membranes of the joints, erythrocytes, liver, kidneys, spleen, lymph nodes, large intestine, appendix, thymus gland).

The reservoir and sources of infection are various animals, mainly pigs, cattle and small cattle, dogs, rodents, and others. Infection from humans occurs rarely and only Y. enterocolitica; with pseudotuberculosis, it is believed that a sick person is not dangerous to others. Various agricultural as well as domestic animals are susceptible to pathogens. The main reservoir of the pathogen and the source of human diseases – synanthropic and other rodents. They are highly susceptible to Yersinia, are common almost everywhere, always have the opportunity to infect with their secretions food, water and soil, where the pathogen not only persists for a long time, but also reproduces under certain conditions. In the population of mouse-like rodents, the alimentary route of transmission of the pathogen is realized. Natural foci form in the habitats of these animals in certain biotopes.

The causative agent of pseudotuberculosis refers to facultative parasites that can inhabit and multiply both in the body of warm-blooded animals and humans, and in environmental objects — soil, water, and plant substrates. Therefore, soil may also be an important reservoir of Y. pseudotuberculosis. The role of rodents in the spread of pseudotuberculosis is negligible.

The transmission mechanism is fecal-oral, the leading transmission route is food. The transmission of pathogens is realized when eating raw or improperly heat-treated meat, dairy and vegetable products, including those stored in the refrigerator. Unpretentiousness of Yersinia to habitat conditions and the ability to multiply at low temperatures contribute to their accumulation in products of animal and vegetable origin. An epidemiological survey of a large number of outbreaks of pseudotuberculosis allowed us to establish that of all foods, vegetables and roots are the most important, then dairy products (cottage cheese, cheese) and, to a much lesser extent, fruits (dried fruits), bakery and confectionery products. The greatest number of outbreaks of pseudotuberculosis occurred after eating fresh cabbage, carrots, green onions, which were stored for a long time in vegetable storage. Low temperature, high humidity in vegetable stores are optimal conditions for the reproduction of Yersinia.

A certain role in this belongs to various objects of the external environment – inventory, packaging, various containers and containers, the contamination of which always takes place. In some vegetable stores in April-May, Yersinia is detected in 40-50% of samples from various vegetables and fruits; and with carrots, cabbage and onions – in 100% of cases. In addition to vegetable stores, a certain role belongs to greenhouses, in which greens, cucumbers, tomatoes, and green onions are grown. The second place is taken by the waterway transfer. It is usually realized when drinking water from open water bodies infected with animal excreta. Not excluded contact and household transmission path. Family and nosocomial outbreaks of yersiniosis were described, in which the source of bacteria was sick adults, hospital attendants or parents caring for children. In isolated cases, diseases associated with blood transfusion (for yersiniosis) and the use of diagnostic equipment (for pseudotuberculosis) were noted.

The natural susceptibility of people is small. In practically healthy individuals, the infectious process is often asymptomatic. Manifest and severe forms occur mainly in children with premorbid background, weakened, against the background of various disorders of the immune status.

Major epidemiological signs. Infections are reported everywhere; morbidity tends to grow further, is both sporadic and outbreak. The increase in morbidity in developed countries is associated with the violation of the ecological balance in nature, an increase in the number of rodents, the acceleration of urbanization, the creation of large warehouses of products, especially vegetable stores, a violation of sanitary and hygienic standards of food storage, the provision of refrigerators for the population, an increase in the share of public catering in cities.

Pseudotuberculosis outbreaks occur in preschool institutions and schools, especially in suburban children’s groups, much less often in enterprises or in educational institutions with public canteens. In recent years, sporadic morbidity has become prevalent. Outbreaks of pseudotuberculosis are common when the incidence of a disease diffusely affects the population of the entire city or settlement, and local, in which the incidence is limited to one team. This is determined by the place of infection of the incoming food: in the first case – the vegetable store or central refrigerators, in the other – the food processing unit of one institution. With pseudotuberculosis, raw vegetables, especially salads made from them, play the main role in the morbidity of people, while non-compliance with sanitary rules of work, technology of preparation and storage of finished products. In rare cases, the transfer factor may be sauerkraut and pickled cucumbers, as well as any food products that are secondarily infected (compotes, milk, cheese, butter). There are outbreaks associated with rusks, biscuits and other baked goods contaminated by rodent secretions.

When yersiniosis flash rarely occur. There are mixed (pseudotuberculosis – yersiniosis) outbreaks, mostly associated with the consumption of infected vegetables. There may be nosocomial infections with a long and sluggish course and intrafamily cases of yersiniosis, usually limited to children and relatives caring for them. The incidence is recorded year round, noting a slight increase in October-November. In recent years, both infections have acquired a similar characteristic of seasonality. Possessing significant resistance to physical and chemical factors, a wide range of adaptive properties, as well as psychophilicity, the causative agents of yersiniosis and pseudotuberculosis can persist for a long time in various products (milk, dairy and meat products) or reside on the surface of vegetables, fruits, greens, bakery products, etc. .d A feature of Yersiniosis, unlike pseudotuberculosis, is its “hidden” character with the presence of a large number of non-manifest forms and a pronounced professional character of infection.

Pseudotuberculosis is registered in all age groups, but to a lesser extent, children under 2 years of age and adults over 50 years of age are ill with them, which is explained by their lesser connection with catering. At the same time, yersiniosis is more common among children from 1 to 4 years. Infection occurs from patients with yersiniosis, and possibly carriers caring for them. With pseudotuberculosis, small children can become ill when vegetables and fruits (juices) are included in the supplements.

Pathogenesis during Yersiniosis and Pseudotuberculosis

In most cases, infection is possible only if a certain concentration of bacteria in the food or water is exceeded. With a high infectious dose on the mucous membranes of the oropharynx, the catarrhal process develops. A known role is played by the acidic barrier of the stomach and the development of catarrhal-erosive changes in it.
In the places of the main localization of pathogens (distal ileum, cecum and the beginning of the colon) inflammatory changes in the intestines of the catarrhal, catarrhal-hemorrhagic and even ulcerous-necrotic nature develop. Under the influence of Yersinia enterotoxin, secretory diarrhea occurs associated with the activation of the adenylate cyclase system in the intestinal epithelium and the accumulation of cyclic nucleotides. In the development of the secretory process, prostaglandins play a certain role. Endotoxin absorption into the blood of pathogens causes intoxication syndrome.

Thus, the occurrence of diarrhea, abdominal pain, dyspeptic disorders and general toxic syndrome is associated primarily with the enterotoxigenic properties of the strains (they are expressed, for example, in serovars 03, 05.27, 07.8 Y. enterocolitica) and the development of endotoxinemia. In such cases, yersiniosis occurs as a localized gastrointestinal form.

The development of generalization of infection, as a rule, is played by the role of Y. enterocolitica strains of serovar 09 and, especially, Y. pseudotuberculosis, which have a solid invasive potential. The latter is due to the ability to synthesize invasins, cytotoxins, hyaluronidase and neuraminidase. Yersinia penetrate into the enterocytes, then into the mucous and submucous layers of the intestine, lymphoid formations of the intestinal wall, regional mesenteric lymph nodes, appendix. Inflammatory changes develop in the affected organs and tissues. Hyperemia and hyperplasia of the mesenteric lymph nodes with the development of microabscesses are characteristic. At the level of the submucous layer of the intestine, Yersinia interact with macrophages incapable of their intracellular killing. As a result, bacteria accumulate in them, stimulating the development of leukocyte infiltration. Reproduction in epithelial cells and macrophages is accompanied by the disintegration of infected cells. Erosion and ulcers, microabscesses in the mesenteric lymph nodes develop.

Pathogenesis of yersiniosis
Invasive strains of Yersinia invade the bloodstream, leading to bacteremia, toxinemia, and the development of the hepatolienal syndrome. Parenchymal diffusion of bacteria causes damage to many organs and systems with the formation of small necrotic foci or microabscesses, as well as changes in the dystrophic nature. In the clinical aspect, these mechanisms correspond to the development of a generalized form of infection with organ lesions of an inflammatory and (extremely rare) septic nature.

In the pathogenesis of yersiniosis, in addition to infectious-toxic, an important role is played by allergic components. Allergic reactions of delayed and immediate types develop, biologically active substances are released.
Since Yersinia is distinguished by antigenic similarity with the antigens of the human connective tissue (myocardial interstitium, synovial membranes of the joints, intestinal endothelium and other organs), during the infectious process, autoantibodies are formed and accumulated, fixed by interstitial cells and the formation of autoimmune complexes. They have a damaging effect on many organs and tissues. In the clinical picture, secondary focal organ disorders of immunopathological genesis are formed. They are the basis of the secondary focal clinical form of yersiniosis, and also contribute to the development of further systemic connective tissue diseases – lupus erythematosus, rheumatoid arthritis, periarteritis nodosa, etc.

For yersiniosis is characterized by the development of recurrent forms and chronic infection. The pathogenetic mechanisms of these conditions are not fully understood. They are associated with the ability of pathogens to intracellular parasitism in the form of L-forms, with the incompleteness of phagocytosis, individual features of cellular and humoral immune reactions, in particular with the formation of autoimmune reactions in individuals with a specific set of tissue antigens (HLA B 27).

In parallel with the development of the infectious process, from the very beginning, protective non-specific and then immune reactions appear. When yersiniosis (to a greater extent with pseudotuberculosis), transient insufficiency of human defense reactions is noted both at the level of specific and non-specific factors (AT IgM and IgG synthesis, opson-phagocytic activity, bacteriolysis, etc.).

The defects of phagocytic potencies of polymorphonuclear leukocytes were established: a decrease in the activity of neutrophils in the acute period of the disease and its normalization at the stage of convalescence. But with the development of so-called secondary focal forms, neutrophil activity remains low.

The peculiarity of Yersinia, which has invasive properties (they are most inherent in the so-called “Kholodovoi” strains grown at 4–12 ° C), is intracellular parasitization, particularly in macrophages, which is largely due to a decrease in the activity of the oxygen-dependent potential of phagocytes.

Violations on the part of cellular immunity were also detected: in the acute stage of the disease, a decrease in the number of T-lymphocytes, a slight increase in B-lymphocytes was observed .; during the recovery period, these changes are leveled. However, with the development of secondary focal forms of this alignment does not occur. We must not forget that a certain immunosuppressive effect may be associated with the appointment of certain antibiotics, such as chloramphenicol. When yersiniosis with a massive dose of infection, the depletion of the T-independent zone of lymph nodes and spleen, the formation of large areas of necrosis in them was revealed. Apparently, this is associated with inhibition of the synthesis of IgM and IgG. The latter, to a certain extent, can also be explained by the natural immunological tolerance of the organism to certain bacterial Ag due to their antigenic similarity with the tissue antigens of the macroorganism.

Based on the study of non-specific and specific protection factors for yersiniosis, a complex of indicators has already been developed that allow predicting its further unfavorable course in the early stages of the disease: an increase in the CEC content, a decrease in the phagocytic function of monocytes and peripheral blood neutrophils, and T-lymphocyte functional activity .
Finally, there are reports on the formation of immune complexes during yersiniosis (in case of dissemination of the pathogen), which are important, in particular, in the development of renal pathology, as well as on the specific role of genetic factors, for example, on the connection between the severity of the disease and blood groups.

Post-infectious immunity with pseudotuberculosis is persistent, but type-specific.

Symptoms of Yersiniosis and Pseudotuberculosis

A single generally accepted clinical classification of yersiniosis still does not exist, although this requires a variety of forms and variants of diseases.

Clinical classification of yersiniosis
The incubation period for pseudotuberculosis varies from 3 to 18 days, with intestinal yersiniosis within 1-6 days. In the clinical manifestations of yersiniosis, a combination of several syndromes is usually observed. The degree of their manifestation varies in different forms and variants of the disease.

General toxic syndrome. It appears most often. At the beginning of the disease, an increase in body temperature up to 38-40 ° C, chills, headache, myalgia, general weakness, loss of appetite are noted. The temperature reaction lasts for 7-10 days, and with a generalized form of the disease – much longer.

Dyspeptic syndrome (abdominal pain, nausea, diarrhea, vomiting). It is more common for lesions caused by Y. enterocolitica, which, together with signs of toxicosis, forms the clinical basis of the gastrointestinal form.

Catarrhal syndrome. They are most often encountered in cases of pseudotuberculosis (up to 80% of cases). Characterized by sore throat, hyperemia of the mucous membrane of the oropharynx, spotted enanthema on the mucous membranes.

Exantmatous syndrome. More often observed with pseudotuberculosis. Manifested spotty-papular (small-dotted, large-spotted, ring-shaped) rash on different areas of the skin. The rash usually appears on the 2-6th day of the disease. The most characteristic is the appearance of a rash of scarlet-tine punctate character on the face and neck in the form of a “hood”, the distal extremities in the form of “socks” and “gloves”. In intestinal yersiniosis, manifestations of exanthema are observed less frequently.

Arthralgic (arthropathic) syndrome. Pains in the joints of the hands, feet, knees, elbows, etc. are noted. Characteristic signs – swelling and restriction of movements in the joints. Along with the pronounced manifestations of toxicosis and the development of the hepatolienal syndrome, these symptoms of yersiniosis are more common with generalized lesions.

Gastrointestinal form. They meet most often (more than 50% of cases) and clinically resembles in other ways other acute intestinal infections, primarily salmonellosis and foodborne toxicoinfections. Dyspeptic syndrome develops in more than half of cases, with the severity and duration of diarrhea more characteristic of intestinal yersiniosis. Intoxication usually occurs simultaneously, but in 1/3 of cases it may precede the development of dyspeptic syndrome.

In 10-20% of cases, at the beginning of the disease, moderate catarrhal phenomena of the upper respiratory tract are noted. In terms of cases, dysuric phenomena (15-17%), arthralgia in the midst of the disease and skin rash on the 2-6th day from the onset of the disease, burning in the palms and soles with their subsequent large-plate scaling occur in the dynamics of yersiniosis. With pseudotuberculosis, as already indicated above, the cardinal signs can be a kind of scarlet-like exanthema and “crimson” language. The rash is more pronounced on the flexor surfaces of the limbs and in the natural folds of the skin. Elements of the rash disappear in a period of several hours to 3-4 days and leave behind a fine-flaked or coarse-lamellar (palms and soles) peeling.

In about half of the patients, a slight enlargement of the liver and a reaction from the peripheral lymph nodes can be observed. Unlike salmonellosis, isolated lesions of the stomach (acute gastritis) are practically not observed in yersiniosis.

With a mild course of the disease, all clinical manifestations can disappear in 2-3 days, in severe cases – 2 weeks or more last. The disease acquires an undulating course with a high body temperature and the development of signs of dehydration.

Such variants of the gastrointestinal form, such as acute appendicitis, terminal ileitis, can unfold either as an independent process or after diarrhea. According to clinical signs, they practically do not differ from acute surgical pathology of the abdominal cavity of a different etiology. When they are stated in cases of yersiniosis, non-abdominal symptoms are usually detected: arthralgia and myalgia, exanthema, vascular injection of the sclera, peripheral lymphadenopathy, hyperemia of the soft palate, “crimson” tongue, liver enlargement. The disease ends in recovery in 3-4 weeks, but sometimes it takes a long relapsing course.

Generalized form. Differs polysyndromism manifestations. Against the background of the development of a general-toxic syndrome with high fever, often marked arthralgia is observed, which hinders the movements of patients (up to 80% of cases), pain during swallowing and catarrhal changes in the upper respiratory tract, exanthema from the 2-3rd day of illness with lesions of the palms and soles up to 90% of cases). Dyspeptic syndrome can occur only at the beginning of the clinical process, but sometimes persists during the height: abdominal pain, usually in the right iliac region, observed in half of patients, usually occurs after a rise in body temperature, nausea is possible in about 25% of cases , vomiting and unstable stool.

In the dynamics of the disease, hepatolienal syndrome develops, high fever persists for a long time and other signs of intoxication are intensified. The disease can take a wave-like or recurrent course. The above symptoms are characteristic of a mixed version of a generalized form.

With prolonged bacteremia and multiorgan dissemination of pathogens, the generalized form of the infection can clinically manifest as hepatitis, pyelonephritis, small focal pneumonia, rarely serous meningitis and yersiniosis sepsis (less than 1% of cases). These conditions develop on the background of subsiding or continuing symptoms described above. Reactive yersiniosis hepatitis is characterized by a short (3-4 days) preicteric period, the development of jaundice at the height of intoxication, short jaundice and hepatomegaly, favorable in most cases with moderately altered bilirubin, aminotransferase, normal thymol breakdown. Unlike viral hepatitis in the blood noted leukocytosis, increased ESR. The transition to the chronic form in yersinia hepatitis is not observed. However, in rare cases, the development of severe hepatitis is observed up to the formation of abscesses in the liver (in children, diabetics, with anemia, cirrhosis).

Secondary focal form. May develop after any of the above forms, it is based on autoimmune reactions with bacterial reactive processes. In some patients, the initial stage of the disease can occur subclinically, but usually this form develops after 2-3 weeks from the onset of the disease and later. The common features of this form also include the undulating course and frequent vascular disorders.

The most frequent variant of the secondary focal form is arthritic (Yersinia polyarthritis) with the lesion of large and small joints (hands, feet). Monoarthritis is less frequently observed (20–25% of cases). Joint lesions are mostly reactive; bacteria are rarely isolated from the intraarticular fluid. Arthritis is asymmetrical, swelling in the joints is noted more often than pronounced hyperemia of the skin. Arthritis is accompanied by intense pain, even with the slightest movement. Growing leukocytosis and ESR, often reveal eosinophilia. Joints of the joints may be accompanied by the development of sacroiliitis and tendovaginitis. The duration of manifestations – from 1 week to 2 years (with a protracted or chronic course), more often – 2-3 months. The prognosis is favorable.

10-20% of patients develop erythema nodosum. Formed from several to 20 subcutaneous nodes and more, large, painful, bright with a typical localization on the legs, thighs, buttocks. The disease lasts from several days to 2-3 weeks, the course is favorable.

Reiter’s syndrome in yersiniosis is expressed in the simultaneous combination of eye lesions (conjunctivitis, scleritis), urethra and joints. The duration of manifestations of myocarditis can reach several months, but its course is benign, circulatory failure does not develop.

Chronic enterocolitis as a variant of the secondary focal form of yersiniosis often develops in the proximal intestine; his development is preceded by symptoms of acute intestinal infections or a generalized form of yersiniosis. Manifestations of enterocolitis can be combined with arthritis, exanthema, catarrhal phenomena of the upper respiratory tract, low-grade fever, asthenia, vegetative-neurotic reactions, etc.

As rare variants of the disease, isolated cervical lymphadenitis is described without previous diarrhea and other clinical signs of yersiniosis. They occur with pain, redness of the skin, swollen lymph nodes and normal or subfebrile body temperature. Rare manifestations of yersiniosis can also be pyodermitis, osteomyelitis, ulceration and skin infiltration.

Relapses and exacerbations
They meet with a frequency of 8 to 55%, the transition to subacute and chronic forms – in 3-10% of cases. Early relapses occur at the beginning of the 3rd week of the disease, therefore in the hospital they often prefer to detain patients until the 21st day from the onset of the disease. The causes of relapses are not well understood, perhaps a short course of treatment and early discharge of patients play a certain role in their formation. In terms of its clinical manifestations, relapses almost repeat the initial symptoms of the disease, but in the erased version.

Numerous and include: myocarditis, hepatitis, cholecystitis and cholangitis, pancreatitis, appendicitis, adhesive intestinal obstruction, intestinal perforation, peritonitis, focal glomerulonephritis, meningoencephalitis, etc. Considering modern pathogenetic data, in one of the latest clinical categories of demographics of coding of dessing of a number of non-derogative forms of demans. certain variants of generalized, secondary focal or gastrointestinal forms of the disease.
Outcomes of yersiniosis usually favorable, excluding the septic variant, leading to the death of up to 50% of patients. The duration of the disease most often does not exceed 1.5 months, however, a prolonged and recurrent course of the disease with a duration of up to 3-6 months or more is observed. Chronic diseases of the musculoskeletal system and gastrointestinal tract, etiologically associated with yersiniosis (more often with pseudotuberculosis), which can be regarded as the residual phase of the process, are described. Chronic collagenosis and autoimmune disorders are possible. There are studies confirming the participation of Yersinia in the development of various thyroid dysfunctions (diffuse toxic goiter, thyroiditis, etc.).

Features of pseudotuberculosis clinic
Clinical manifestations of pseudotuberculosis are characterized by a wide variety of forms and variants. More often the disease develops according to a mixed variant of a generalized form. The incubation period varies from 3 to 18 days, usually 5-7 days. The onset of the disease is distinguished by general toxic signs, arthralgia, abdominal pain, sometimes dyspeptic symptoms, catarrhal symptoms of the upper respiratory tract, enlarged liver, and in some cases, swelling of the face, hands, and feet. After 5-7 days, the peak period begins, lasting from several days to 1 month. During this period, the exanthema develops predominantly of scarlet-like nature with localization in the region of the face, neck and distal extremities, including on the palms and soles. At the same time observe abdominal, hepatitis, arthralgic manifestations. As a rule, manifestations of intoxication dominate over local signs of the disease. One of the varieties of rash – erythema nodosum, often manifested in relapses of the disease. With the development of arthritic syndrome, smoothing of the contours of the joints and skin flushing over them are rarely noted. The recovery period is delayed to 1 month or more. Therefore, the disease is divided into acute (up to 1 month), prolonged (from 1 to 3 months) and chronic (more than 3 months) pseudotuberculosis. The frequency of exacerbations and relapses can reach 20% (from 1 to 3 relapses).

Diagnosis of Yersiniosis and Pseudotuberculosis

Differential diagnosis presents serious difficulties. It should be borne in mind that the development of gastroenteritis, colitis and pyelonephritis of various etiologies, hepatitis, dysentery, rheumatism, eye, surgical diseases, collagen diseases.

One of the main and most frequent differences of yersiniosis, especially of the generalized form, is the simultaneous appearance of several syndromes in the clinical picture: general toxic, dyspeptic, catarrhal, exanthematic, arthralgical (arthropathic), hepatolienal. The gastrointestinal form, clinically in many respects similar to salmonellosis, foodborne toxicoinfections, in some cases distinguishes the possibility of simultaneous development in different patients of more prolonged and severe diarrhea, dysuric events, arthralgia, exanthema, and a small increase in the liver.

Manifestations of yersinia appendicitis or terminal ileitis are usually preceded by gastroenteritis and / or extra-abdominal symptoms.
Reactive yersiniosis hepatitis is distinguished by a shorter jaundice and hepatomegaly period than in viral hepatitis, moderate increases in bilirubin and aminotransferase, leukocytosis, increased ESR.

Yersinia polyarthritis is distinguished by asymmetry of the lesions and mild hyperemia of the skin over the affected joints.

The most difficult differential diagnosis of such manifestations of yersiniosis, as erythema nodosum, Reiter’s syndrome, myocarditis, thyroiditis and chronic enterocolitis. In such cases, the patient’s indications of the recently postponed “diarrheal states” and “food poisoning” give a certain direction to the differential diagnosis.

Laboratory diagnosis
Patients’ feces, washings from the pharynx, urine, sputum, cerebrospinal fluid, blood, bile, surgical material (mesenteric lymph nodes, intestinal tracts), as well as sectional material – altered organs and tissues, intestinal contents, blood clots can serve as seeding material. Pathogens can also be distinguished from the objects of the environment – vegetables and fruits, from salads, milk, fish and dairy products, as well as from the washes from equipment and containers. Positive results of the study are obtained in 9-15% of cases with the sporadic nature of the disease and in 25-50% with outbreaks. The low efficiency of excretion is due to the insignificant amount of Yersinia in the material under study (especially in the blood) and the high contamination of the objects under study with accompanying microflora. Bacteriological analysis requires quite a long time – from 7 to 30 days.
More promising are express methods for determining Yersinia antigens in coproextracts, saliva, urine, and blood of patients in RCA, RLA, PHII, ELISA. The effectiveness of the RCA increases with the weighting of the clinic, exacerbations and relapses of the disease.

Laboratory diagnosis of yersiniosis
The frequency of positive results ranges from 55 to 90% (with the gastrointestinal form of the disease).
From the 6th-7th day of illness, RA and RIGA are used with their re-staging in 5-7 days. RNGA gives 40-70% positive results; The minimum diagnostic antibody titer is 1: 200. However, it is necessary to take into account the possibility of the appearance of antibodies in diagnostic titers only at a later date, after the 21st day from the onset of the disease. When setting RA with live cultures of Yersinia, it is possible to detect antibodies to a greater number of serovars than in the RNAA and in a greater percentage of cases. The minimum diagnostic antibody titer is at least 1: 160.

Treatment of Yersiniosis and Pseudotuberculosis

In recent years, it has become increasingly common to practice inpatient treatment with full-fledged prolonged courses of etiotropic therapy, even for mild forms of the disease. This is associated with an increase in recurrent forms and chronic yersiniosis.

When conducting etiotropic therapy, it is preferable to prescribe antibiotics and fluoroquinolones; the treatment is completed no earlier than the 10-12th day after the normalization of body temperature. Prescribing drugs after the 3rd day of the disease does not prevent the development of exacerbations, relapses and chronic disease. In the generalized form of Yersiniosis, preference is given to combined parenteral antibacterial therapy; in cases of recurrence, it is necessary to conduct repeated courses of antimicrobial therapy with a change of drugs.

Of the other etiotropic drugs, cotrimoxazole is sometimes used (2 tablets 2 times a day), nitrofuran preparations (0.1 g 4 times a day), but these drugs are less effective than antibiotics.

Detoxification therapy with the use of crystalloid and colloid solutions is carried out according to generally accepted schemes. Prescribed rehydron, citroglucosolan, kvartasol, 5% glucose solution, gemodez, reopolyglukine, plasma, vitamins of groups C and B.

With the development of secondary focal form should be carried out active desensitization; at the same time etiotropic therapy becomes secondary. Antihistamines, nonsteroidal anti-inflammatory drugs are shown, with persistent erythema nodosum, prednisone is recommended in a short course for 4-5 days at 60-80 mg / day.

When polyarthritis prescribed antirheumatic drugs, physical therapy, physiotherapy activities; local relief of glucocorticoids brings temporary relief.

In the treatment of yersiniozov also recommend the use of antioxidants (eg, vitamin E), enzymes (hilak-forte), tranquilizers, cardiovascular drugs. The popularity of immunocorrectors (cimetidine, methyluracil, pentoxyl, etc.) and immunostimulants (normal human immunoglobulin, polyglobulin) is growing.
Given the high likelihood of developing dysbiosis, recommend probiotics.

Prevention of Yersiniosis and Pseudotuberculosis

The basis of prevention is targeted hygiene measures. Of primary importance is the prevention of microbial contamination of vegetables, fruits and root crops, which requires compliance with sanitary rules for the maintenance of vegetable stores, temperature and humidity conditions for storing vegetables. It is necessary to limit the use of food products used without heat treatment. Also important are activities that make food and drinking water inaccessible to rodents, birds and domestic animals. To do this, carry out the fight against rodents and carry out sanitary inspection of food, water supply, compliance with the technology of processing and storage of food. Prevention of yersiniosis in animals provides for strict adherence to the veterinary-sanitary and zoohygienic rules for the care of animals, aimed at creating optimal conditions for the keeping and feeding of animals and preventing their infection through environmental objects. Deratization measures at catering facilities, water supply and livestock complexes are of significant importance. Of great importance is the conduct of a wide sanitary and educational work among the population, especially among workers of food and food enterprises. One of the most important measures to prevent the incidence and outbreaks of pseudotuberculosis is a monthly bacteriological and serological study of vegetables and root crops in vegetable stores, as well as inventory. In the case of detection of the causative agent of pseudotuberculosis or its antigen on products or equipment of vegetable stores, it is necessary to immediately prohibit the eating of contaminated vegetables in raw form and allow their use only after heat treatment for cooking first and second courses. Drinking water should be consumed only after boiling. No means of specific prophylaxis.

Activities in the epidemic focus
Hospitalization of the patient is carried out according to clinical indications. Patients are discharged from the hospital after complete clinical recovery, not earlier than the 10th day of normal body temperature and with the normalization of laboratory parameters. Control single examinations before discharge are advisable only for intestinal yersiniosis. Bacterium carriers are treated on an outpatient basis without release from work. Carriers working on food processing units for the period of outpatient treatment are transferred to other work not related to cooking. Children who have had pseudotuberculosis and yersiniosis, especially severe forms, are subject to clinical supervision by a local pediatrician to prevent recurrences, protracted course and complications. With a favorable course of observation spend 21 days; in case of complaints, clinical manifestations, laboratory examination is prescribed, in case of indications – hospitalization and treatment.

Persons belonging to decreed categories are subjected to bacteriological examination before discharge (1 stool analysis 2 days after the end of treatment). When a negative result of the survey they are immediately allowed to work. After discharge, follow-up care is recommended for all patients who have been ill for at least 3 months. At the same time, depending on the organ damage, clinical blood tests, urine tests, biochemical studies (bilirubin, cholesterol, liver function tests, ALT and ACT, total protein and its fractions), PHA, should be carried out. If necessary, consult a therapist, rheumatologist, gastroenterologist, and other specialists.

At the end of the follow-up observation, individuals of declassified categories carry out two control bacteriological analyzes of feces with an interval of 2-3 days.

Activities in children’s groups and family foci. When a child is ill, all family members are subject to bacteriological examination; shown observation (thermometry, inspection) for 7-10 days. Emergency prophylaxis is not performed. In the event of major outbreaks in closed institutions (pioneer camp, sanatorium, kindergarten, boarding school), it is allowed to deploy an inpatient hospital for patients with mild forms under the conditions provided by qualified medical assistance, the possibility of laboratory examination and adherence to the anti-epidemic regime. Discharges of the patient (feces, urine) are disinfected with a 3-5% bleach solution with an exposure of at least 1 hour, and only after that are they thrown into the sewers or cesspools.