CHOLERA is an acute infectious disease characterized by diarrhea, vomiting, and severe dehydration.
The causative agents are cholera vibrios: classic cholera vibrio and vibrio El Tor. Vibrio cholerae are mobile, slightly bent in the form of a comma; spores and capsules do not form. The causative agents of cholera are obligate aerobes. When cultivating them in peptone water, superficial growth is observed in the form of a bluish-gray delicate film, easily destroyed by shaking. Cholera vibrios have H- and O-antigens.
From patients with acute gastrointestinal diseases, as well as from sewage and open reservoirs, so-called NAG-vibrios are sometimes isolated, not agglutinated by typical cholera serums. Given the complexity of the differentiation of cholera and NAG-vibrios, the selection of these pathogens is carried out the same anti-epidemic measures as with cholera. The causative agents of cholera are resistant to the environment. In water, they survive from several days to several weeks, in feces without drying - 217 days, but they are very sensitive to sunlight, drying, disinfectants, especially acids, quickly die when boiled. Vibrio El Tor compared with the classical more stable in the external environment. The long-term survival of Vibrio cholerae contributes to the contamination of open water. In them, the vibrio can develop, accumulating in the inhabitants of water bodies (fish, crabs, mollusks, etc.).
Sources of infection are patients with cholera, vibrio-carrying convalescents and healthy (transient) carriers. Patients with a pronounced clinical picture of cholera are excreted into the external environment per day up to 10 - 30 l of feces, in 1 ml of which contains from 106 to 109 vibrios. Vibrio-carrier reconvalescents emit pathogens on average for 2–4 weeks, transient carriers — 9–14 days. The intensity of the release of vibrios they have less - from 102 to 109 vibrios in 1 g of feces. The leading route of cholera transmission is water. Infection occurs when drinking infected water, using it to wash vegetables, fruits, while bathing. Food cholera outbreaks usually occur among a limited number of individuals who consume infected products (milk, fish, shrimp, crabs, clams). When the contact-domestic pathway pathogen can be entered into the mouth with his hands or through objects infected with the secretions of patients. The spread of cholera can contribute to flies. Susceptibility to cholera is high. The disease leaves behind a relatively stable immunity. Repeated cases of the disease are rare. Artificial immunity to cholera is inadequate, since the effectiveness of existing vaccines is still low.
Clinical picture . The incubation period ranges from several hours to 5 days (on average 2-3 days). The disease can occur in typical and atypical forms. There are mild, moderate and severe forms of the disease, which depend on the degree of dehydration and developing hemodynamic and metabolic disorders. Diarrhea is the initial, characteristic symptom of cholera, occurs acutely, often suddenly at night or in the morning. Patients feel the imperative urge to defecate without tenesmus and abdominal pain. The stool is abundant, the stool initially has a fecal character with particles of undigested food, then becomes liquid, watery, with floating flakes. In the future, they can take the form of rice broth with the smell of fish or raw grated potatoes. The patient's appetite decreases, there is thirst and muscle weakness. Body temperature usually remains normal, in severe cases - low.
On examination, an increase in the pulse rate and a dry tongue are detected. The stomach is retracted, painless. The disease can quickly end with recovery or progress. In the latter case, the chair becomes more frequent (more than 10 times a day), plentiful (fountain) joins without nausea and epigastric pain, repeated vomiting . Vomit first contain food residues, then become watery, yellow in color. Profuse diarrhea and repeated profuse vomiting quickly (within a few hours) lead to marked dehydration. Muscle weakness, thirst, dry mouth builds up. Due to the violation of the water-salt balance and the accumulation of lactic acid in some patients, short-term convulsions of the gastrocnemius muscles, feet and hands appear, diuresis decreases. The skin is dry, its turgor is lowered, unstable cyanosis is noted. The mucous membranes are also dry. Often there is hoarseness, increased heart rate, lowering blood pressure.
The lack of treatment or its failure leads to an increase in dehydration. Facial features are sharpened, cyanosis and dryness of mucous membranes and skin are enhanced. Skin turgor decreases, on hands it becomes wrinkled (“hands of the washerwoman”). Muscular relief of the body, aphonia , tonic convulsions of individual muscle groups are expressed, urination stops. Body temperature at the same time normal or reduced.
In severe cases of cholera, severe dehydration can develop within 12 hours. Diarrhea and vomiting subsequently become less frequent or completely stop. Often the tip of the nose, auricles, lips, marginal margins of the eyelids acquire a purple or almost black color. The facial features sharpen even more, cyanosis appears around the eyes (a symptom of "dark glasses"), the eyeballs sink deep, turned upwards. Consciousness saved for a long time. The voice is soundless, the body temperature drops to 35 - 34 ° C. The skin is cold to the touch, easily gathered in folds and does not smooth out for a long time (“cholera fold”). Pulse is arrhythmic, weak filling and tension, blood pressure is almost not defined. Shortness of breath increases, arrhythmic breathing, shallow breathing (up to 40 - 60 in 1 min.). Convulsions of a tonic nature extend to the pectoral muscles, to the diaphragm, which leads to excruciating hiccups. Stomach, sunken, soft, painful during muscle cramps. Anuria develops. In the absence of adequate treatment, consciousness is lost, coma and asphyxia occur.
The atypical forms of the disease include fulminant and erased. In the form of cholera with lightning, there is a sudden onset and rapid development of dehydration, convulsions of all muscle groups, meningeal and encephalitic symptoms. The worn form is characterized by poor symptoms and a mild course of the disease.
Cholera El-Thor is clinically similar to classical cholera, but more often it proceeds easily, atypically, with long-term vibrionovydeleniem.
Complications of the disease are associated with the development of hypovolemic shock and the addition of secondary bacterial flora: acute renal failure , pulmonary edema, pneumonia , abscesses, cellulitis of various localization.
Diagnosis is based on a combination of anamnestic, epidemiological, clinical and laboratory data. It is necessary to take into account the sequence of development of the symptoms of the disease, the absence of chills and abdominal pain, the nature of the stool and vomit (at normal or low temperature). The bacteriological method is fundamental in the laboratory diagnosis of cholera. Emetic and fecal masses are the material for the study, and in the period of convalescence, and in bacteria excreta - duodenal contents. Material for the study must be taken before the appointment of antibiotic therapy and not earlier than 36-48 hours after its completion. Crops of the material are produced on liquid and solid nutrient media no later than 3 hours from the moment it is taken.
Cholera often has to be differentiated from some foodborne toxicoinfections and escherichiosis. In these cases, attention should be paid to the epidemiological history and early bacteriological examination of the discharge of the patient.
Treatment . Compensation for the loss of fluids, electrolytes and correction of metabolic disorders is of paramount importance in therapy. For dehydration, immediate intravenous (or intraarterial) rehydration is required to fill the fluid deficit. For this purpose, polyionic pyrogen-free solutions are used.
Rehydration measures are divided into primary rehydration - replenishment of an already existing water and electrolyte deficiency and compensatory rehydration - replenishment of ongoing water and electrolyte losses. Rehydration therapy should be carried out in specialized departments or wards equipped with appropriate equipment (Phillips beds or “cholera bed”, scales, dishes to collect and measure the amount of feces, vomit, urine). Primary rehydration in patients with severe forms of dehydration is carried out by intravenous administration of a standard Trisol polyionic solution, whose composition is close to the salt composition of cholera patient stool .
In recent years, the Chionzol, Acesol, Lactasol, Kvartasol, and Disol polyionic solutions are increasingly used. In infusion therapy of patients with a significant degree of dehydration, the amount of fluid injected in the first 1–1.5 hours should be about 10% of the patient’s body mass. Before infusion, the solution should be heated to 38 - 40 ° C. The first 2–4 liters of solution are injected in streams (80–120 ml / min), and then drip at a rate of 30–60 ml / min. At the end of the primary rehydration, they switch to compensatory rehydration, the volume and speed of which are determined by the continuing loss of water and salt. For this purpose, every 2 hours, the volume of feces and vomit is measured (separately from urine), the hematocrit, the level of sodium and potassium in the blood serum, pH are determined and the necessary corrections are made to the therapy being carried out.
Occasional vomiting does not contraindicate continued rehydration. After cessation of vomiting, tetracycline is administered orally at a dose of 0.3-0.5 g 4 times a day for 5 days. Against the background of antibacterial therapy, the duration of diarrhea is reduced and bacteriological rehabilitation of the ballroom is accelerated. The timely delivery of complex therapy currently provides a reduction in the mortality rate from cholera (1-3% or less).
Discharge of patients from the hospital is usually done on the 10–11th day of illness after clinical recovery and the three negative results of bacteriological examination of stool. Bacteriological examination is carried out no earlier than 24 to 36 hours after the cancellation of antibiotics for 3 consecutive days. The first intake of feces is carried out after the patient is given a saline laxative (20-30 g of magnesium sulfate). Convalescents produce bacteriological examination of duodenal contents. For the treatment of vibriovydelitel use tetracycline at a dose of 0.3 g 4 times a day for 3 to 5 days, and with the re-allocation of vibrios - chloramphenicol 0.5 g 4 times a day. Special diet sick cholera is not required. From the first days they prescribe diet No. 4, and from the 3-5th day of treatment it is possible to switch to a common table. After stool normalization, it is recommended to include foods rich in potassium (dried apricots, bananas, tomato and orange juice) in the diet.
Prevention. The system of measures for the prevention of cholera is aimed at preventing the introduction of this infection into our country from disadvantaged areas, the implementation of epidemiological surveillance and the improvement of the sanitary and communal state of populated areas. For persons arriving from countries where there is trouble for cholera, medical observation is established for 5 days, during which a single bacteriological examination is performed. With the threat of cholera, compulsory hospitalization and bacteriological examination of all patients with acute intestinal diseases is carried out. Conduct immunization against cholera population of the area.
When isolating the cholera pathogen from environmental objects, the following is provided for: temporary ban on the use of water from open reservoirs; temporary increase in the multiplicity (1 time in 10 days) of bacteriological studies of open water reservoirs, drinking and technical water supply systems, wastewater and the contents of cesspools; triple bacteriological examination for cholera of all patients with acute intestinal diseases; temporary hyperchlorination of water for drinking and technical water pipes. In the outbreak of cholera, a complex of anti-epidemic measures is carried out, the main of which are: urgent isolation, hospitalization, examination and treatment of identified cholera patients and vibrio-carriers; active identification of patients through household bypass, provisional hospitalization and examination of all patients with acute gastrointestinal diseases for cholera; identification of contact persons, isolation of them or only medical observation for 5 days, bacteriological examination for cholera and prophylactic treatment with antibiotics (tetracycline - 0.3 g 3 times a day for 4 days); epidemiological examination in the outbreak; current and final disinfection; sanitary-hygienic measures and sanitary-educational work; epidemiological analysis of the outbreak. For the purpose of specific prophylaxis, choleragen - atoxin is used. Vaccinations produce a single needleless injection at a dose of 0.8 ml of the drug for adults. According to epidemiological indications, revaccination can be carried out no earlier than 3 months after the primary vaccination.