Yersiniosis is an acute anthropozoonous intestinal infection accompanied by a toxic-allergic reaction, characterized by multi-foci. Yersiniosis is characterized by a fecal-oral transmission pathway. Livestock, rodents and dogs are the reservoir of infection. The incubation period of yersiniosis lasts no more than a week. The clinic consists of a general toxic syndrome, spotty papular rashes, dyspeptic disorders; possible hepatosplenomegaly, arthropathic syndrome, the development of acute appendicitis, generalized form of yersiniosis. The diagnosis is established on the basis of the isolation of yersinia in various biological environments of the patient.
Yersiniosis is caused by the bacterium Yersinia enterocolitica, a motile gram-negative facultative anaerobic bacillus. Yersinia perfectly tolerate low temperatures, in the refrigerator at 4-6 ° C are able not only to persist, but also to multiply on products. (Yersiniosis is often called “refrigerator disease”). Bacteria easily tolerate freezing and subsequent thawing, persist for a long time in water, soil, but are sensitive to sunlight, drying, boiling and chemical disinfectants. Yersinia secrete enterotoxin, cytotoxins and endotoxin.
The reservoir and source of yersiniosis are mainly animals: various rodents, livestock (mainly pigs), dogs. People can spread the infection, but infection from humans is quite rare. In cities, the infection is mainly spread by rodents, it is their clusters that form epidemic foci of infection during outbreaks. Yersiniosis is transmitted through the fecal-oral mechanism by food and water. Food products of animal origin, insufficiently treated thermally, water sources contaminated with the feces of sick animals, contribute to the implementation of infection routes. In rare cases, a contact-household transmission path is implemented (as a rule, it is associated with a low hygienic culture).
A person’s natural susceptibility to yersiniosis is low. Healthy people practically do not get sick with clinical forms of infection. Severe and manifest course is characteristic of children, people suffering from immunodeficiency conditions, chronic diseases that contribute to a pronounced weakening of the protective properties of the body. Epidemic outbreaks of yersiniosis are quite rare and most often occur with the mass consumption of vegetables contaminated with microbes.
Yersiniosis is divided into gastrointestinal, generalized and secondary-focal forms. The gastrointestinal form includes gastroenteritis, thermal ileitis and acute yersiniosis appendicitis. The generalized form can occur in the form of sepsis, hepatitis, meningitis, pyelonephritis, pneumonia, as well as in a mixed form.
The secondary focal form is divided into yersiniosis arthritis, myocarditis, enterocolitis, erythema nodosum and Reiter’s syndrome. Yersiniosis can occur in mild, moderate and severe forms, acquire an acute cyclic, chronic and recurrent course.
The incubation period of intestinal yersiniosis is 1-6 days, the clinical picture is usually represented by several syndromes. Most often there is a general toxic syndrome, manifested in the form of fever reaching 38-40 ° C, chills, headaches, general weakness, aching muscles and joints. Appetite is reduced, in severe cases, disorders of central nervous activity may occur. The febrile period usually lasts 7-10 days (significantly lengthening in the case of generalized yersiniosis). When the gastrointestinal form of general intoxication is usually accompanied by dyspepsia (nausea, vomiting, diarrhea, abdominal pain).
In rare cases, with yersiniosis, an exanthema appears. The rashes are spotty-papular, small-point or large-spotted (sometimes ring-shaped), appear on various areas of the skin, most often in the lower extremities (a symptom of “socks” and “gloves”). The rash may be accompanied by burning in the palms, leaving areas of peeling behind. In some forms of yersiniosis, arthropathic syndrome (arthralgia) is noted. The joints of the extremities (hands, feet, elbows and knees) are painful, swollen, movements in the affected joints are limited. With generalized yersiniosis, hepatolienal syndrome (enlargement of the liver and spleen) may be noted.
In clinical practice, the gastrointestinal form of yersiniosis is most common. The disease proceeds like other infectious and toxic intestinal lesions, characterized mainly by manifestations of intoxication and (in half of cases) dyspeptic disorders. Intoxication usually precedes, but can develop simultaneously with dyspepsia. Sometimes this form of infection is accompanied by rashes, catarrhal or arthropathic syndrome. Severe intoxication can contribute to the development of hepatosplenomegaly, and sometimes there is moderate poly-lymphadenopathy (lymph nodes are enlarged, but painless and do not lose mobility).
Depending on the severity of the course, the duration of the disease ranges from 2-3 days to two or more weeks. Long-term intestinal yersiniosis acquires a wave-like character, signs of dehydration appear. Acute appendicitis or terminal ileitis with yersinia lesions do not differ in course from those pathologies caused by non-specific flora. These conditions can either develop independently or have a secondary character, being the result of the progression of a gastrointestinal or other form of infection.
In the generalized form, there is a variety of symptoms. The general toxic syndrome is intense, the fever reaches critical figures. In the vast majority of cases (80%), arthralgic syndrome is pronounced, catarrhal phenomena (sore throat, rhinitis, cough) are noted, a rash on the palms and soles may occur on the 2-3 day (less often in another localization). Dyspeptic phenomena can occur at the initial stage and rarely persist in the midst of the disease. Half of the patients report abdominal pain (mainly at the bottom from the right), a quarter – nausea, vomiting and diarrhea.
With the progression of the infection, the liver and spleen increase, the course can become undulating and recurrent. Similar symptoms may accompany a mixed form of yersiniosis. In the case of prolonged bacteremia and contamination by microorganisms of various organs and systems, signs of secondary hepatitis, pneumonia, pyelonephritis, serous meningitis and (extremely rarely) sepsis may appear. In this case, the initial symptoms may subside, or persist and progress.
The secondary focal form can be a consequence of any of the above-described forms of infection, usually it develops 2-3 weeks after the onset of the disease or at a later date. This form is associated with the formation of pathological reactivity and autoimmune damage to organs and tissues. In rare cases, it proceeds without a pronounced clinic. Yersiniosis reactive polyarthritis is most common. The joints of the extremities (feet, hands) are usually affected, more often asymmetrically. Monoarthritis is rare (no more than a quarter of cases). The joints are swollen, there is no hyperemia of the skin above them. The course of polyarthritis can become prolonged or chronic, on average its duration is 2-3 months.
In 10-20% of cases, yersiniosis occurs in the form of nodular erythema. Subcutaneous nodules form on the shins, thighs and buttocks, painful, large. The quantity can vary from several pieces to two or more dozens. After 2-3 weeks, the nodules resolve. Reiter’s syndrome is a combination of conjunctivitis, urethritis and arthritis. Yersiniosis myocarditis often lasts for several months, but usually in a mild benign form, cardiovascular insufficiency does not develop.
The secondary focal form can occur in the form of enterocolitis (usually develops in people with a history of intestinal infections). The lesion is localized mainly in the upper intestine, often combined with other variants of infection (arthritis, exanthema, catarrhal syndrome), may be accompanied by asthenic symptoms (asthenia) and an increase in body temperature to subfebrile figures. Rare symptoms of yersiniosis include a variety of lymphadenopathies, pyoderma, osteomyelitis. A common feature of reactive multiple organ pathologies in yersiniosis is a wave-like course and a tendency to vegetative-vascular disorders.
Complications of yersiniosis due to polymorphism of manifestations and a tendency to form autoimmune reactions are quite diverse. These can be inflammatory diseases of organs (myocarditis, hepatitis, cholecystitis, pancreatitis), surgical pathologies (adhesive disease, intestinal obstruction, appendicitis, perforation of the intestinal wall and peritonitis), diseases of the nervous system (meningoencephalitis), urinary (glomerulonephritis) and musculoskeletal (arthritis, osteomyelitis) apparatus.
Isolation of the pathogen is possible from feces, blood, bile, urine, cerebrospinal fluid of patients, in addition, back-seeding of flushes from the pharyngeal mucosa, sputum can be carried out. The pathogen is detected in flushes from environmental objects, objects, from food products. However, bacteriological diagnosis requires considerable time (often up to 30 days). As a rapid analysis, reactions are used to determine pathogen antigens in biological fluids (using ELISA).
The sensitivity of PKA increases with severe course and chronization of the process. From the 6-7 day of the disease, RA and RIGA become positive, after 5-7 days, the antibody titer is measured again. A patient with yersiniosis may need to consult a gastroenterologist, cardiologist, nephrologist or neurologist. With the development of complications, ECG, Echo-KG, ultrasound of the abdominal cavity, etc. are indicated.
In modern clinical practice, yersiniosis is treated inpatient, prescribing prolonged etiotropic agents even with mild forms of the disease. This tactic is caused by the frequency of chronic infection and the development of a recurrent nature of the course. Etiotropic therapy includes a course of antibiotics and fluoroquinolones, lasting for the entire febrile period and 10-12 days after. Late administration of drugs (after 3 days of clinical symptoms) does not guarantee the prevention of complications and chronization of infection. The generalized form is treated comprehensively (prescribe drugs of various groups of antibacterial agents parenterally), to prevent relapses, antibiotics are changed throughout the course.
The complex of non-specific therapeutic measures is selected depending on the patient’s condition and the course of the disease. According to indications, detoxification solutions are prescribed (dextran, colloidal and crystalloid mixtures), antihistamines, anti–inflammatory groups of nonsteroidal drugs, and, if necessary, prednisone (hormonal anti-inflammatory drugs are often used for topical use). Patients may be shown vitamin therapy, digestive enzymes, probiotics for the correction of intestinal biocenosis, as well as means to increase immune protection (immunomodulators, human immunoglobulin).
Prognosis and prevention
Despite the variety of complications and forms of the disease, the course of yersiniosis is usually benign, fatal outcomes are extremely rare. An unfavorable prognosis is characterized by yersiniosis sepsis, which ends in death in half of the cases.
Prevention of yersiniosis implies the observance of personal hygiene, including food hygiene, as well as sanitary and epidemiological control of medical and preventive institutions and catering and food industry enterprises. A significant measure is the control over the condition of water sources. One of the preventive measures is the deratization of settlements and agricultural land.