Shigellosis (acute shigellosis) is potentially dangerous and extremely easily transmitted infectious disease of the colon with enteral mechanism of infection caused by bacteria of the genus Shigella and proceeding with intoxication.Symptoms appear after an incubation period of one to four days, and usually subside after 10 days.In severe cases, the disease can last up to six weeks, but in most cases the disease has a soft shape.Dysentery is most common in children aged one to four years.It is common in crowded areas with poor sanitation, and often occurs in the form of epidemics;to stop the spread of the disease, sick people are isolated and introduced quarantine in the epidemic.How to use folk remedies in this illness, see here.
etiology. causative agent of Shigella (dysentery) Shigella genus is a group of microorganisms.Shigella - still, small rods 2-3 mm x 0.5-0.7 mm, not stained by Gram, do not form spores, facultative aerobes.Resistant to physical and chemical factors, can withstand temperatures
based biochemical characteristics and antigenic structure (serovar) put classification.
In subgroup A includes views of S. dysenteriae, including 1-10 minutes Serov-ry: the first of them - Grigoriev-Shiga, 2nd serovar - Fittings-Schmitz, 3-7 minutes serovars - Lardzha-Sachs;8-10 minutes serovars - provisionally.Sub Newcastle - is S. flexnery, 6th serovar that a number of features closer to S. boydii.
The subgroup included in the form of S. flexnery, including serovars 6, 4 of them are divided into podserovary.
subgroup C presented views boydii, involving 15 serovars.
Shigella subgroup D are combined into a single serovar - view of S. sonnei.
Biological properties of Shigella.Shigella characterized by the following biological properties: a high degree of virulence (the most virulent of the family Enterobacteriaceae), multidrug resistance, the most common antibiotic tetracycline, aminoglycoside and chloramphenicol and resistant to high and low temperatures, are able to maintain the viability and virulence at 30-40 ° C.
One of the features of their biological properties is the ability to produce exotoxins: heat-labile and heat-stable enterotoxin, cytotoxin.Intensity enterotoxin production in S. dysenteriae 1000 times higher than in other species.
endotoxin, which is O-antigen, is released by autolysis of bacteria, leading to antigenemia.There are factors of pathogenicity, have the ability to a penetrated Hela cells, and invasiveness.Invasiveness revealed the genetic control mechanism associated with the transfer of plasmids 120 MM MD, from which elimination of lost property invasiveness and virulence.
Shigella belongs to the highly adhesive, vysokotoksigennym, highly virulent species of Enterobacteriaceae.
• dysentery bacillus - a bacterium that is embedded in the tissue lining the colon, can cause dysentery.
• Other pathogens dysentery amoeba are parasitic bacteria and E. coli, Yersinia and others.
• dysentery bacillus is usually spread through contact with the feces of an infected person.
• Neglect thorough hand washing after a bowel movement may contribute to contamination dysentery.
• Flies can carry bacteria from feces (usually in areas with poor sanitation).
• Use of contaminated food or water can lead to infection of dysentery.
epidemiology of shigellosis. shigellosis are among the diseases that are ubiquitous, and, according to WHO, occupy one of the leading places in the structure of diarrheal diseases.
Shigella specific weight in Russian among intestinal infections is an average of 30%, the proportion of children in the total incidence of shigellosis is 60-70%.In recent years the Russian Federation there is a tendency to an increase in the incidence of shigellosis.Thus, the incidence of shigellosis Flexner grew by 47%, shigellosis Sonne - 24%.
source Shigella is a sick person or MbT.The greatest danger is posed by the epidemic, patients, including blurred, atypical forms, which are released into the environment with faeces 30 times more pathogens than MbT or convalescents.Typically, Shigella bacterial excretion in 80% of patients discontinued after 2-3 weeks from the onset of the disease, 20% of patients continued for several weeks or even months.Duration Shigella bacterial isolation contribute to the patient's existing chronic diseases of the gastrointestinal tract, liver, intestinal dysbiosis, immune deficiencies, eating disorders, as well as irrational feeding, early transfer to artificial feeding, rickets in infants.Persistent Shigella bacterial isolation contributes to the inadequate treatment of acute shigellosis.
Shigella spread by the fecal-oral transmission mechanism, which includes the transfer of the pathogen infection water, food and domestic routes, and by flies.Moreover, for each type of Shigella, there are main and additional transmission path.The main way of transmission, ensuring the preservation of a particular pathogen as a species, is for Shigella Grigoriev-Shiga household,
Flexner - water, Sonne - food.Factors transmission can respectively be infected water, milk, sour cream, cottage cheese.Failure to comply with hygiene standards can become infected and serve as transfer factors and other products.
In infants pathway Shigella mostly contact-home, older children - most often the food and water.
Shigellosis is an infection, which is characterized by high sensitivity in all age groups.However, the greatest incidence is registered as a child (up to 60-70% of all patients).The incidence in different age groups of children is not the same.Most often affects children from 2 to 7 years (the proportion - up to 70%), visiting the children's groups.The incidence of shigellosis among the "organized" children 3.5 times the incidence among children who do not attend child care centers.Children of the first year of life are ill shigellosis much less.
factors of nonspecific protection of an organism against Shigella.From nonspecific protection factors encountered on the way Shigella primarily should indicate hydrochloric acid, bile and enzymes secreted by the mucous membrane of the gastrointestinal tract.
mechanical barrier function is performed by peristalsis, promote mechanical removal of Shigella from the intestinal lumen, and an intact intestinal epithelium.
a definite barrier function is performed by the normal intestinal microflora, competing with pathogens for a place of attachment to the mucosa, producing a number of substances that suppress the growth of pathogenic bacteria and determining the activity of the intestinal epithelium.
are very important factors of local immunity (secretory immunoglobulin A, macrophages, properdin, lysozyme).
nonspecific resistance of the organism depends on several factors: the supply of patients, age, presence of concomitant acute and chronic diseases, the environment.
• First, watery diarrhea.It can go in diarrhea with mucus and blood.
• Voltage at the bowel, accompanied by pain in the rectum.
• Pain in the abdomen;pain throughout the body.
• Nausea and vomiting.
• Rapid dehydration and weight loss (young children and the elderly are particularly susceptible to dehydration).
conditions of acute shigellosis. development of acute shigellosis is defined as the state of the organism, and the pathogen response.
Factors predisposing to the development of acute shigellosis, are chronic diseases of the liver, the gastrointestinal tract, intestinal dysbiosis, disfermentoz, disturbances in the system of local immunity, hereditary enzimopatii.
development of the infectious process is also determined by the properties and the number of pathogens, density of their distribution on the surface of the intestine.A large number of Shigella contained in contaminated food entering the body of the child, can cause the development of severe forms of the disease with a short incubation period, and the development of neurotoxicity, an infectious-toxic shock.At the same time, children in the first years of life with immunodeficiency disease may occur as a result of infection, even small doses of shigella.
main pathogenetic mechanisms of acute shigellosis. disease develops only in contact with the pathogen in the gastrointestinal tract through the mouth.Throughout the gastrointestinal tract by the action of nonspecific protection factors Shigella microorganism death occurs with release of endotoxin, which is absorbed into the bloodstream.Phase toksinemii in shigellosis is characterized by involvement in the pathological process of all organs and systems, especially the nervous system, and is non-specific in nature.Develops primary infectious toxicosis.
Colonization and Shigella adhesion occurs mainly in the large intestine, distal his department.Formed inflammation, disrupting peristalsis and bowel motility.All the above leads to the development of invasive diarrhea syndrome.
have young children and a massive invasion (food route of infection) there is an initial toxic damage of glands as the thick and thin intestine, leading to disruption of the processes of digestion and absorption of food ingredients, the accumulation of osmotically active substances in the small intestine and the development of entero-colitiscurrent version of shigellosis.
Features immunity after acute shigellosis. Immunity after suffering shigellosis and species-specific antimicrobial.The patient's blood shigellosis accumulate agglutinins, precipitin and complement-haemagglutinin antibodies.The titer of specific antibodies is low, it declines rapidly, and after 5-15 months.antibodies disappear completely.Specific humoral immunity is monospecific character.Of great importance is the local, mucosal immunity, which is a cell-tissue character.Immunity intestinal epithelial cells to the pathogen is due to increased production of secretory immunoglobulin A, activation of tissue macrophages, mast cells, histiocytes, lysozyme.
Pathological changes in shigellosis.Morphological changes shigellosis in children detected in all parts of the gastrointestinal tract, but predominantly in the distal colon.Intensity of morphological changes can be very different from acute catarrh to fibrinous necrotic, fibrinous-ulcerous.Less commonly observed diphtheritic colitis.
The children of the first year of life is dominated by the catarrhal and follicular and ulcerative lesions of the large intestine form.
most significant changes in the large intestine, usually develop in shigellosis Grigoriev-Shiga, less severe - at Flexner shigellosis, the lightest - in shigellosis Sonne.
almost always along with catarrhal colitis occurs rarely - catarrhal-hemorrhagic enteritis and catarrhal, more rarely - erosive gastritis.
Histological examination of the sigmoid and rectum revealed damage to the musculo-intestinal (auerbahovskoe) and submucosal (Meissner) plexus.
Reparation mucosa of the gastrointestinal tract occurs much later than the clinical recovery (from 5 weeks. 2-3 months.).
dystrophic changes observed in many organs.In marked pulmonary edema with hemorrhage secondary perivascular leukocyte reaction in the myocardium - swelling and disintegration glybchaty cardiomyocytes, hepatic - Degenerative changes in hepatocytes in the brain - perivascular edema, hemorrhage.
Causes of death: toxic shock - at 60-70%, swelling of the brain - 15-20%, acute heart failure - at 10-15%, pneumonia - 5-7% of deaths.
I. The form:
2. Atypical: subclinical, asymptomatic, hypertoxic, dyspeptic.
II.According to the severity of the process:
a) with a predominance of general changes;
b) with a predominance of local changes;
c) mixed form.
III.In course of the disease:
a) acute (up to 1 month).
c) prolonged (up to 3 months).;
g) chronic (more than 3-4 months.) - Continuous, recurrent.
IV.By the nature of complications: otitis media, intestinal dysbiosis, anemia and other
V. Mixed infection..
Clinic. incubation period ranges from 6-8 hours to 7 days, on average - 2-3 days.
While infecting the baby food by the incubation period is short and disease characterized by rapid onset, pronounced obscheinfektsionnym syndrome, possible development of neurotoxicity, an infectious-toxic shock.
contact-household way of infection leads to the manifestation of infection after 4-7 days, which is manifested in the form of a typical gastrointestinal symptoms and moderately expressed symptoms of intoxication.
Support diagnostic criteria of acute shigellosis flowing typical:
• Acute onset of the disease.
• Increasing the temperature to febrile digits subfebrile and duration from 1 to 3 days.
• Development of various degrees of intoxication, the possible formation of infectious toxicity, neurotoxicity.
• Clinical signs of distal colitis.
• invasive diarrhea.
Clinical manifestations of toxicity in acute shigellosis.Specific shigellosis toksinemiya develops most often in older children, manifests itself as a primary neurotoxicosis with characteristic clinical picture.Defeat toxins cardiovascular system may be accompanied by a fall in blood pressure and development collaptoid state.In addition, increased permeability and fragility of the vascular wall lead to the development of local hemorrhagic syndrome, and in patients with severe - DIC.
Clinical signs of distal colitis in patients with acute shigellosis. Manifestations distal colitis in patients with acute shigellosis are:
• lean loose stools with mucus, green, blood-streaked, losing fecal character ( "a rectal spittle");
• painful bowel movements - tenesmus;
• spasms and soreness of the sigmoid colon with abdominal palpation;
• compliance or gaping anus;
• «false desires" to defecate.
distal colitis patients registered typical forms of shigellosis.
Symptoms of mild acute shigellosis .Mild form of shigellosis occur in 50-60% of patients and is characterized by the absence or mild symptoms of intoxication (low-grade fever, slight lethargy, loss of appetite, vomiting, single).Stool frequency does not exceed 5 times per day, fecal droppings do not lose their character, pasty or liquid, with an admixture of a small amount of slime;blood in feces is usually absent and only some patients observed in some portions as thin streaks in the mucus.Palpable spasm or compacted sigmoid colon.Abdominal pain are absent or occur only during defecation.Characteristic phenomena sfinkterita and compliance anus.
In the study of internal organs, most patients abnormalities were detected.
scatological study reveals mucus, fresh white blood cells in the first days of the disease, with a 3-day dramatically changed, is very rarely found isolated red blood cells.
When rektomanoskopii revealed mild pronounced catarrhal, catarrhal, follicular Proctosigmoiditis.
moderate forms of acute shigellosis .