El Tor cholera

　　The pathogenic bacterium of El Tor cholera is the El Tor cholera vibrio. The only way for the El Tor cholera vibrio to enter the human body is through the diet, from the mouth through the stomach to the small intestine. Since the cholera vibrio is Gram-negative and highly sensitive to gastric acid, normal gastric acid can kill the El Tor cholera vibrio. However, when the gastric acid is temporarily low or the number of invasive bacteria increases, the El Tor cholera vibrio that has not been killed by gastric acid can pass through the gastric acid barrier and enter the alkaline environment of the small intestine. After passing through the mucus layer on the surface of the small intestinal mucosa, it adheres to the surface of the small intestinal epithelial cells and multiplies here, producing a large amount of highly toxic exotoxins.

　　This exotoxin can increase the level of cAMP (cyclic adenosine monophosphate) in the epithelial cells of the small intestinal mucosa, causing a large amount of sodium ions and water to continuously flow out of the cells into the extracellular space, which leads to a large amount of intestinal fluid being secreted into the intestinal tract. The secretion is large, exceeding the ability of the intestinal tract to reabsorb water and sodium. Clinically, this results in severe diarrhea, reflexive severe vomiting, massive loss of water and salt, severe dehydration, and subsequently, a significant reduction in plasma volume, a lack of salt in the body, blood concentration, and the occurrence of peripheral circulatory failure. Not only that, severe vomiting and diarrhea can lead to the loss of other components, potassium and sodium deficiency, muscle spasms, acidosis, and even shock and acute renal failure.

　　The most characteristic clinical manifestation of cholera is severe diarrhea and vomiting, which can lead to the loss of a large amount of water and electrolytes, causing electrolyte and acid-base imbalances. Subsequently, insufficient effective blood volume can lead to shock. Among them, hypokalemia-induced hypokalemic syndrome is one of the complications of cholera, mainly manifested as muscle weakness, reduced intestinal peristalsis, palpitations, arrhythmias, hypotension, and so on.

　　Due to the failure to correct shock in a timely manner and hypokalemia, renal failure may occur. Renal failure is a pathological condition in which part or all of the kidney function is lost. It is characterized by reduced urine output and azotemia, and in severe cases, anuria may occur, leading to death due to uremia.

　　In addition, severe cholera can also cause acute pulmonary edema. This is due to severe vomiting and diarrhea, resulting in the loss of a large amount of electrolytes and water, causing metabolic acidosis within the body. Metabolic acidosis can lead to pulmonary hypertension, and the loss of water requires a large amount of non-alcoholic beverages, and because of the addition of a large amount of saltwater without alkali, it further aggravates pulmonary hypertension, thus forming a vicious cycle, leading to the occurrence of acute pulmonary edema.

　　After human infection with El Tor cholera vibrio, a large proportion of asymptomatic carriers, that is, individuals without clinical symptoms, are present. Among the symptomatic cases, most are mild. The El Tor cholera vibrio infection in humans does not immediately cause disease and has a certain incubation period. The incubation period can range from a few hours to 5 days, with 1 to 2 days being the most common. Most patients have an abrupt onset and no obvious prodromal symptoms. The course of the disease is generally divided into three phases:

　　① The Excreting and Vomiting Period

　　It usually starts with sudden diarrhea, followed by vomiting. There is generally no obvious abdominal pain or urgent need to defecate. There may be several bowel movements a day or even more, with a large amount of excrement. Initially, it is yellowish water, which soon turns into rice water-like stools. A few patients may have bloody watery stools or tarry stools. After diarrhea, there may be projectile and copious vomiting, initially containing stomach contents, followed by stools, and vomiting is often not accompanied by nausea. Some patients may have diarrhea without vomiting. Due to severe diarrhea and vomiting, there is a significant loss of body fluids and electrolytes, leading to circulatory failure, manifested as a decrease in blood pressure, weak pulse, and decreased urine output or anuria. There is a significant loss of electrolytes such as sodium and potassium in the blood, which can cause muscle cramps, especially in the gastrocnemius and rectus abdominis muscles of the lower legs. Deficiency of potassium can cause hypokalemia, manifested as decreased muscle tone, disappearance of tendon reflexes, bloating, tachycardia, and irregular heartbeat. Due to the large loss of bicarbonate ions, metabolic acidosis may occur, leading to deep and rapid breathing, and in severe cases, unconsciousness and a decrease in blood pressure.

　　② Dehydration and collapse phase

　　The appearance of patients is very obvious, and severe cases may have deep eye sockets, hoarseness, dry and wrinkled skin, loss of elasticity, a sunken abdomen, dry lips and tongue, thirst, cold extremities, and body temperature often dropping below normal. Muscles may spasm or twitch. Patients are critically ill, but if they are treated promptly and properly, they can turn the danger into safety and gradually return to normal.

　　③ Recovery period

　　A few patients (children are more common) may develop a febrile reaction at this time, with body temperature rising to 38-39°C, generally lasting for 1-3 days before spontaneously resolving, so this period is also called the reaction period. The average course of the disease is 3-7 days.

　　Currently, most cases of cholera have mild symptoms similar to enteritis. They are often misdiagnosed or missed, leading to the spread of infection.

　　As a Class A infectious disease, the main source of transmission of El Tor cholera is patients and carriers. Carriers are divided into three types: healthy carriers, latent carriers, and post-infection carriers. Therefore, the first preventive measure is to control the source of infection: set up intestinal clinics, timely detect and isolate patients, and achieve early diagnosis, early isolation, early treatment, and early reporting. Suspected patients or contacts should be isolated and observed for 5 days. During the quarantine period, doxycycline (doxycycline) can be taken orally 3 times a day or tetracycline can be taken daily, for 5 days. Isolation can be lifted after three negative fecal tests.

　　The transmission of El Tor cholera is mainly through the excrement (urine, feces) of carriers, which contacts water and spreads after being contaminated. Food, hands, and flies can also spread cholera. Therefore, the second preventive measure is to cut off the route of transmission: strengthen health education, actively carry out mass patriotic health campaigns, improve environmental hygiene, manage water sources, feces, and food, eliminate flies, and develop good hygiene habits.

　　The third preventive measure is to protect susceptible populations, actively exercise, improve the ability to resist diseases, and can be vaccinated with cholera vaccine. Oral whole-cell, lipopolysaccharide, or toxoid (subunit B) vaccine may provide better protection.

　　The diagnosis of this disease requires the assistance of relevant examinations to confirm the diagnosis, in order to distinguish it from other diseases and avoid misdiagnosis.

　　1. Blood examination

　　Erythrocyte and hemoglobin levels increase, white blood cell count increases, neutrophils and large monocytes increase. Serum potassium, sodium, chloride, and bicarbonate decrease, blood pH decreases, and blood urea nitrogen increases. Before treatment, due to the outward movement of potassium ions from cells, serum potassium may be within the normal range. When acidosis is corrected, potassium ions move into the cells and hypokalemia appears.

　　2. Urinalysis

　　A small number of patients may have protein, red and white blood cells, and casts in their urine.

　　3. Pathogen examination

　　(1) Routine microscopy: Mucus and a few red and white blood cells can be seen.

　　(2) Smear staining: Gram staining of smears from feces or early culture can be observed under a microscope, showing Gram-negative slightly curved bacteria.

　　(3) Drop examination: Fresh feces can be used for drop or dark field microscopy examination, and the active,穿梭状bacteria can be seen.

　　(4) Immobilization test: Take the surface growth of the water sample feces or alkaline peptone water enrichment culture for about 6 hours from acute patients, first perform dark field microscopy to observe motility. If there is a穿梭样 movement, add one drop of 01 group polyvalent serum. If it is 01 group cholera vibrio, due to the antigen-antibody reaction, it will coagulate into lumps, and the movement of the vibrio will stop. If the movement cannot be stopped after adding 01 group serum, the test should be repeated with 0139 serum.

　　(5) Enrichment culture: All suspected cholera patients' feces should be subjected to enrichment culture in addition to microscopic examination. Feces should be collected before the use of antimicrobial drugs and should be sent to the laboratory for culture as soon as possible. The enrichment culture medium generally uses alkaline peptone water with a pH of 8.4, and a bacterial film can form on the surface after 6 to 8 hours of culture at 36～37℃. At this time, further isolation and culture should be carried out, and motility observation and immobilization test should be performed, which will help to improve the detection rate and early diagnosis.

　　(6) Isolation and culture: Commonly used gentamicin agar plates or alkaline agar plates. The former is a highly selective culture medium, and the cholera vibrio can grow into small colonies within 8 to 10 hours at 36～37℃. The latter requires 10 to 20 hours of culture. Select suspicious or typical colonies, and use the cholera vibrio 'O' antigen antiserum for slide agglutination test. If positive, a report can be issued. In recent years, DNA probes for cholera toxin genes have also been used abroad for colony hybridization, which can quickly identify toxigenic 01 group cholera vibrios.

　　(7) PCR detection: The application of PCR technology for rapid diagnosis of cholera has been recently introduced in foreign countries. It distinguishes cholera strains from non-cholera vibrios by identifying the subunits of the cholera toxin gene (CtxA) and the toxin synergistic pilus gene (TcpA) in the PCR products. Then, the different DNA sequences of TcpA gene are used to differentiate classical biotype and El Tor biotype cholera vibrios. Results can be obtained within 4 hours, and it is claimed that it can detect less than 10 cholera vibrios per ml of alkaline peptone water.

　　(8) Differential tests: Identification of classical biotype, El Tor biotype, and 0139 cholera vibrio.

　　4. Laboratory examination

　　(1) Routine blood tests and biochemical tests: Wbc↑N↑Rbc↑Na+↓k+↓cl-HCO-3↓Bun↑cr↑.

　　(2) Urinalysis examination: A little red blood cells, leukocytes, protein, casts.

　　(3) Feces examination:

　　① Routine examination a little mucus, red blood cells, white blood cells.

　　② Smear staining Gram-negative curved vibrios.

　　③ Drop test active motile vibrios.

　　④ Braking test growth in alkaline peptone water for 6 hours.

　　⑤ Enrichment culture in 8.4 pH alkaline protein peptone water at 36-37℃ for 6-8 hours → bacterial film → motility braked isolation culture.

　　⑥ Perform agglutination test with antiserum isolated from O antigen

　　(4) Serological immunological examination Antibody against bacteria, antibody against enterotoxin, antibody against agglutinin.

　　5, Routine examination

　　(1) Direct microscopic examination

　　(2) Isolation and culture: Directly inoculate the vomit and diarrhea, or enrich it with alkaline peptone water first, and then inoculate it on庆大霉素琼脂 (Cephalosporin agar) and other culture media, it is easy to detect the cholera vibrio. Using fluorescent antibody to detect cholera vibrio in feces, results can be obtained within 1 to 2 hours.

　　(3) Serological examination: Serological agglutination test can be performed. Take one serum sample on the 1st to 3rd day and the 10th to 15th day after onset, if the antibody titer of the second serum is 4 times or more than 4 times higher than that of the first serum, it has diagnostic reference value.

　　(4) Agglutination test - rapid diagnosis: A large number of vibrios are present in the watery stools of acute patients. If the drop test is positive, add cholera polyvalent serum without preservatives (concentration of 1:64) and the bacteria will stop moving and clump together within a few minutes, which is positive.

　　El Tor type cholera is a type of cholera. To do a good job of dietetic care for cholera, we need to first understand some characteristics of the cholera vibrio.

　　Cholera is more likely to occur in the summer and autumn seasons. The cholera vibrio has 'five fears': afraid of dryness but not moisture, afraid of acidity but not alkalinity, afraid of saltiness but not blandness, afraid of chlorine but not alcohol, afraid of tea but not milk. Therefore, we should not drink unboiled water, change the bad habits of using unboiled water to gargle, wash utensils, soak vegetables, aquatic products, etc., as these habits increase the chance of cholera being spread through water. Especially in the summer and autumn seasons, this should be done even more strictly.

　　Flies can carry bacteria during an outbreak of the disease. Some have detected El Tor cholera vibrio from flies caught on an epidemic ship with cholera and from flies caught in the epidemic area. Therefore, the cleanliness of the home must be ensured. Pay close attention to doing a good job of eliminating mosquitoes and flies.

　　For those already infected, the following diet therapy can be tried:

　　1, Egg flower syrup:40 grams of egg flower, double the amount for those collected from fresh products. Boil in clear water and drink the decoction after adding an appropriate amount of sugar for seasoning, and discard the residue.

　　2, Portulaca oleracea and mung bean syrup: 50 grams of Portulaca oleracea or 100 grams of fresh Portulaca oleracea, 50 grams of mung beans, decocted, add an appropriate amount of brown sugar for seasoning, and take it twice a day.

　　3, Fresh Portulaca oleracea and mung bean soup:120 grams of fresh Portulaca oleracea (30 grams for the dried version), 30 to 60 grams of mung beans. Take the decoction and eat it once a day, for 3 to 4 consecutive days.

　　4, Huai medicine crisp:250 grams of Huai medicine, 10 grams of black sesame seeds, 100 grams of sugar, and an appropriate amount of vegetable oil. The skin of the Huai medicine is peeled and cut into diamond-shaped pieces. The black sesame seeds are toasted and set aside. Heat the pot, add vegetable oil and Huai shan, and only add sugar and black sesame seeds.

　　In the treatment of El Tor type cholera, traditional Chinese medicine has different formulas according to symptoms. For mild cases: symptoms include sudden onset of vomiting and diarrhea, the stool at the beginning is loose, followed by clear diarrhea or like milky water, not very smelly, abdominal pain or no pain, chest and diaphragm stuffiness, cold limbs, white greasy fur, weak and soft pulse. In this kind of treatment, it is advisable to disperse cold and dry dampness, aromaticize turbidity, and use Huoxiang Zhengqi Powder with modifications: Huoxiang 8g, Suzhu 8g, Baizhi 8g, Jiegeng 8g, Fuling 8g, Banxia 10g, Houpu 10g, Gancao 6g. And combine with Chuyang Zhengqi Pill to enhance the effect of warming the middle and dispelling cold, drying dampness and turbidity. When the decoction is not ready, it can be taken first as a pill, or take Biewen Dan to aromaticize and open the orifices, dispel evil and turbidity; or take Laihuo Dan to assist Yang in transforming turbidity, regulate Qi and harmonize the middle, in order to achieve emergency relief.

　　And for severe patients: symptoms include continuous vomiting and diarrhea, vomiting and diarrhea like milky water, pale complexion, sunken eye sockets, sunken finger pads, cold limbs, sweating on the head and face, muscle spasm, pale tongue, white fur, deep and fine pulse. In treatment, it is advisable to warm and tonify the spleen and kidney, rescue the Yang and reverse the Qi, and use Aconitum Lateralis Preparatum Decoction with modifications, and use Xingjun San 0.3-0.6g to dispel evil and open the orifices: prepared aconite 10g (boiled for 45-60 minutes), red ginseng 10g (separated and mixed), fried white atractylodes 9g, burned ginger 5g, fried licorice 6g.

　　If the symptoms are profuse sweating, cold limbs, hoarse voice, stiffness and twisting of the limbs, a fine pulse that is about to break, it belongs to the exhaustion of Yin and Jing and the separation of Yin and Yang, and the danger is imminent. If a large dose of acrid and warm herbs is suddenly used to rescue the Yang, then worry about the further depletion of body fluid, and the method of using counter-herbs to treat should be used, and 5g of Jiang juice fried Chuanlian can be added to the original formula, or use Tongmai Baining added with pig bile decoction, so that the bitter and acrid herbs complement each other, and Yin and Yang are harmonized. Raw aconite 15g (boiled for 45-60 minutes, until the mouth tastes no pungent and spicy sensation), dried ginger 9g, fried licorice 6g, pig bile 10ml (if there is no pig bile, use goat bile instead).

　　It should be noted that in severe cases of cold dysentery, once vomiting and diarrhea occur, muscle atrophy, coldness and dizziness, excessive sweating and restlessness, thirst for drinking and vomiting, should not be mistaken for heat syndrome. The vomiting and diarrhea of cold dysentery are relatively slow, and the key points of differentiation are that the vomit and diarrhea are not very smelly, the limbs are cold, the tongue is pale and white, and the pulse is weak.