CHOLERA is an acute infectious disease characterized by diarrhea, vomiting, and severe dehydration.
The causative agents are cholera vibrios: the classic cholera vibrio and El Tor vibrio. Vibrio cholerae are mobile, slightly curved in the form of a comma; spores and capsules do not form. The causative agents of cholera are obligate aerobes. When cultivated on peptone water, surface growth is observed in the form of a bluish-gray delicate film, which is easily destroyed by shaking. Cholera vibrios have H- and O-antigens.
From patients with acute gastrointestinal diseases, as well as from wastewater and open water bodies, sometimes the so-called NAG vibrios are distinguished, which are not agglutinated by typical anticholera sera. Given the difficulty of differentiating cholera and NAG vibrios, the same anti-epidemic measures are carried out when these pathogens are isolated, as with cholera. Cholera pathogens are sustainable in the environment. In water, they survive from several days to several weeks, in stools without drying - 217 days, but are very sensitive to sunlight, drying, disinfectants, especially acids, quickly die when boiled. Vibrion El Tor compared to the classic is more stable in the external environment. Long-term survival of cholera vibrios contributes to the pollution of open water. In them, the vibrio can develop, accumulating in the inhabitants of water bodies (fish, crabs, mollusks, etc.).
Sources of infection - patients with cholera, convalescents-vibriocarriers and healthy (transient) carriers. Patients with a pronounced clinical picture of cholera emit up to 10-30 l of stool per day into the external environment, 1 ml of which contains from 106 to 109 vibrios. Reconvalescents-vibriocarriers secrete pathogens on average within 2-4 weeks, transient carriers - 9-14 days. The intensity of vibrio excretion is lower - from 102 to 109 vibrios per 1 g of feces. The leading transmission of cholera is water. Infection occurs when drinking infected water, using it to wash vegetables, fruits, and when bathing. Outbreaks of cholera usually occur among a limited number of people who consume infected foods (milk, fish, shrimp, crabs, mollusks). In the contact-domestic way, the pathogen can be introduced into the mouth by hand or through objects infected with secretions of patients. Flies can contribute to the spread of cholera. Susceptibility to cholera is high. The transferred disease leaves behind a relatively stable immunity. Repeated cases of the disease are rare. Artificial immunity to cholera is inferior, since the effectiveness of existing vaccines is still low.
The clinical picture . The incubation period ranges from several hours to 5 days (an average of 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 imperative urge to defecate without tenesmus and abdominal pain. The stool is plentiful, bowel movements at first have fecal character with particles of undigested food, then they become liquid, watery, with floating flakes. In the future, they can take the form of a rice broth with the smell of fish or raw grated potatoes. The patient's appetite decreases, thirst and muscle weakness appear. Body temperature usually remains normal, in severe cases - low.
On examination, increased heart rate, dry tongue. The abdomen is pulled in, painless. The disease can quickly end in recovery or progress. In the latter case, the stool becomes more frequent (more than 10 times a day), abundant (fountain) joins without nausea and pain in the epigastrium, repeated vomiting . Vomit initially contains food debris, then become watery, yellow. Profuse diarrhea and repeated profuse vomiting quickly (within a few hours) lead to severe dehydration. Muscle weakness, thirst, dry mouth are increasing. Due to the violation of the water-salt balance and the accumulation of lactic acid in some patients, short-term convulsions of the calf 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 are hoarseness, increased heart rate, decreased blood pressure.
The absence of treatment or its insufficiency leads to an increase in dehydration. Facial features are sharpened, cyanosis and dryness of the mucous membranes and skin are intensified. Skin turgor decreases, on wrists it becomes wrinkled (“laundress hands”). The muscular relief of the body, aphonia are expressed , tonic convulsions of certain muscle groups appear, urination stops. The body temperature is normal or reduced.
In severe cases of cholera, severe dehydration can develop within 12 hours. Diarrhea and vomiting in the future become less frequent or completely stop. Often the tip of the nose, auricles, lips, marginal edges of the eyelids acquire a purple or almost black color. Facial features are sharpened even more, there is cyanosis around the eyes (a symptom of “dark glasses”), eyeballs are deeply sunken, turned up. Consciousness is stored for a long time. The voice is soundless, body temperature drops to 35 - 34 ° C. The skin is cold to the touch, easy to fold and does not straighten out for a long time (“cholera fold”). The pulse is arrhythmic, weak filling and tension, blood pressure is practically not determined. Shortness of breath increases, breathing is arrhythmic, shallow (up to 40-60 in 1 min). Seizures of a tonic nature extend to the pectoral muscles, to the diaphragm, which leads to a painful hiccup. The abdomen is sunken, soft, painful during muscle cramps. Anuria develops. In the absence of adequate treatment, consciousness is lost, coma and asphyxia occur.
Atypical forms of the disease include fulminant and erased. With the fulminant form of cholera, a sudden onset and rapid development of dehydration, cramps of all muscle groups, meningeal and encephalitic symptoms are observed. The erased form is characterized by scanty symptoms and a mild course of the disease.
Cholera El Tor is clinically similar to classical cholera, but often proceeds easily, atypically, with prolonged vibration.
Complications of the disease are associated with the development of hypovolemic shock and the attachment of a secondary bacterial flora: acute renal failure , pulmonary edema, pneumonia , abscesses, phlegmon 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 reduced temperature). The bacteriological method is the main in the laboratory diagnosis of cholera. The material for the study is vomit and feces, and during the period of convalescence and bacterial excreta - duodenal contents. Material for the study must be taken before the appointment of antibiotic therapy and no earlier than 36-48 hours after its completion. Crops of the material are carried out on liquid and solid nutrient media no later than 3 hours after taking it.
Cholera often has to differentiate from some foodborne toxicoinfections and Escherichiosis. In these cases, attention should be paid to the epidemiological history and early bacteriological examination of the patient's discharge.
Treatment . The leading value in therapy is the compensation of fluid loss, electrolytes and the correction of metabolic disorders. With dehydration, immediate intravenous (or intra-arterial) rehydration is required to fill the fluid deficiency. For this purpose, polyionic pyrogen-free solutions are used.
Rehydration measures are divided into primary rehydration - replenishment of the existing water-electrolyte deficit and compensatory rehydration - replenishment of ongoing losses of water and electrolytes. Rehydration therapy should be carried out in specialized departments or wards equipped with appropriate equipment (Phillips beds or “cholera bed”, scales, dishes for collecting and measuring the volume of bowel movements, vomit, urine). Primary rehydration in patients with severe forms of dehydration is carried out by intravenous administration of the standard Trisol polyionic solution, the composition of which is close to the salt composition of the cholera patient's feces: 1 g of pyrogen-free bidistilled water contains 5 g of sodium chloride, 4 g of sodium bicarbonate and 1 g of potassium chloride .
In recent years, the polyionic solutions “Chlosol”, “Acesol”, “Lactasol”, “Kvartasol”, “Disol” are increasingly used. During 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 weight. Before infusion, the solution should be heated to 38 - 40 ° C. The first 2–4 L of the solution is injected jet (80–120 ml / min), and then drip at a rate of 30–60 ml / min. At the end of primary rehydration, they begin to perform compensatory rehydration, the volume and speed of which are determined by the ongoing loss of water and salts. For this purpose, the volume of feces and vomit is measured every 2 hours (separately from urine), the hematocrit, the level of sodium and potassium in the blood serum, the pH are determined and the necessary adjustments are made to the therapy.
Vomiting that sometimes appears does not contraindicate continued rehydration. After the termination 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 antibiotic therapy, the duration of diarrhea is reduced and bacteriological rehabilitation of the ballroom is accelerated. The timely implementation of complex therapy currently provides a reduction in mortality from cholera (1-3% or less).
Patients are usually discharged from the hospital on the 10–11th day of illness after clinical recovery and three negative results of bacteriological examination of feces. A bacteriological study is carried out no earlier than 24 to 36 hours after the abolition of antibiotics for 3 consecutive days. The first stool sampling is carried out after the patient has been prescribed a salt laxative (20-30 g of magnesium sulfate). In convalescents, a bacteriological study of the duodenal contents is performed. Tetracycline is used at a dose of 0.3 g 4 times a day for 3 to 5 days to treat vibrious excretors, and chloramphenicol 0.5 g 4 times a day for repeated isolation of vibrios. A special diet for cholera patients is not required. From the first days, a diet No. 4 is prescribed, and from the 3-5th day of treatment, a transition to the general table is possible. 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, carrying out epidemiological surveillance and improving the sanitary and communal condition of populated areas. For persons arriving from countries where there is a dysfunction of cholera, medical supervision is established for 5 days, during which a single bacteriological examination is performed. If there is a risk of cholera, they undergo mandatory hospitalization and bacteriological examination of all patients with acute intestinal diseases. Immunize against cholera population of the area.
When isolating the causative agent of cholera from environmental objects, provide for: temporary prohibition of the use of water from open water bodies; a temporary increase in the multiplicity (1 time in 10 days) of bacteriological studies of open reservoir water, drinking and technical water supply systems, sewage and the contents of cesspools; triple bacteriological examination for cholera of all patients with acute intestinal diseases; temporary hyperchlorination of drinking water and technical water supply. In the focus of cholera, a complex of anti-epidemic measures is carried out, the main of which are: urgent isolation, hospitalization, examination and treatment of identified patients with cholera and vibriocarriers; active identification of patients by courtyards, provisional hospitalization and screening for cholera of all patients with acute gastrointestinal diseases; identification of contact persons, isolation of them or only medical observation for 5 days, bacteriological examination for cholera and preventive treatment with antibiotics (tetracycline - 0.3 g 3 times a day for 4 days); epidemiological examination in the outbreak; ongoing and final disinfection; sanitary-hygienic measures and sanitary-educational work; epidemiological analysis of the outbreak. For the purpose of specific prevention, cholerogen - atoxin is used. Vaccinations are made once with a needleless injector at a dose of 0.8 ml of the drug for adults. Revaccination according to epidemiological indications can be carried out no earlier than 3 months after the initial vaccination.