Typhoid and paratyphoid fever

　　Typhoid and paratyphoid fever are acute enteric infectious diseases caused by Salmonella typhi and Salmonella paratyphi A, B, and C. They can cause outbreaks due to contamination of water and food sources. The disease is distributed throughout China and occurs sporadically throughout the year, with the highest incidence in summer and autumn. The disease affects children and young adults more frequently.

　　The causative agent of this disease is Salmonella typhi, which belongs to the D group (group) of the genus Salmonella, is Gram-negative, has a short rod-shaped morphology, is 1 to 3.5 μm long, 0.5 to 0.8 μm wide, has flagella, is motile, does not produce spores, has no capsule, can grow on general culture media, and grows better in media containing bile.

　　1. Salmonella typhi has a strong viability in nature, generally surviving in water for 2 to 3 weeks, in feces for 1 to 2 months, and can not only survive but also reproduce in milk. It can withstand low temperatures and can survive in frozen environments for several months. However, it is relatively susceptible to light, heat, dryness, and disinfectants. Direct sunlight for a few hours will kill it, and it will die immediately after being heated to 60℃ for 30 minutes or after boiling. It is killed in 3% carbolic acid solution within 5 minutes, and the residual chlorine in disinfected drinking water reaching 0.2 to 0.4 mg/L can kill it quickly.

　　2. The Salmonella typhi bacteria only infect humans and do not infect animals under natural conditions. This bacterium can release strong endotoxins when the bacterial body is lysed, which plays a relatively important role in the occurrence and development of the disease. Injecting a small amount of endotoxin into the veins of humans or domestic rabbits can cause chills, fever, discomfort, and a decrease in white blood cells, which are very similar to the symptoms of typhoid patients. The somatic (‘O’), flagellar (‘H’), and surface (‘Vi’) antigens of Salmonella typhi can produce corresponding antibodies, but these are not protective antibodies. Due to the strong antigenicity of the ‘O’ and ‘H’ antigens, they are often used in serum agglutination tests (Widal test) to assist in clinical diagnosis and can also be used to produce typhoid vaccines for preventive vaccination. The ‘Vi’ antigen is found in newly isolated (especially from patient blood) strains and can interfere with the bactericidal efficacy and phagocytic function in serum, which is an important factor in determining the virulence of Salmonella typhi. However, the antigenicity is not strong, and the agglutination titer of the ‘Vi’ antibodies produced is generally low and short-lived. After the pathogen is cleared from the human body, the ‘Vi’ antibody titer decreases rapidly. Although the detection of ‘Vi’ antibodies is not very helpful for the diagnosis of the disease, it is helpful to identify carriers. Salmonella typhi with ‘Vi’ antigens can be lysed by specific bacteriophages. Using type ‘Vi’ II bacteriophages, Salmonella typhi can be divided into about 100 phage types, which is helpful for tracing the source of infection.

　　Typhoid and paratyphoid fever can be complicated with intestinal hemorrhage and intestinal perforation. For intestinal hemorrhage, treatment includes strengthening anti-infection and hemostasis, blood transfusion for large amounts of bleeding, and considering surgery if hemostasis fails. For intestinal perforation, treatment includes strengthening anti-infection, correcting electrolyte and water imbalances, gastrointestinal decompression, and selecting surgery according to specific circumstances.

　　The prognosis of the disease is closely related to the patient's condition, the degree of toxicemia, age, whether there are complications or associated diseases, the virulence of the bacteria, the timing of treatment, the method of treatment, and whether the patient has received preventive vaccination. Before the advent of antimicrobial drugs, the mortality rate of typhoid fever was about 20%, mostly due to severe toxicemia, malnutrition, pneumonia, intestinal hemorrhage, and intestinal perforation. Since the application of chloramphenicol and other antimicrobial drugs, the mortality rate has明显下降 significantly.

　　What are the symptoms of typhoid and paratyphoid fever? The introduction is as follows:

　　First, symptoms

　　The typical natural course of typhoid fever lasts about 4 weeks and can be divided into 4 stages:

　　1. Initial stage.1. The initial stage: Most cases (75% to 90%) are of slow onset, with fever being the earliest symptom, often accompanied by general malaise, fatigue, decreased appetite, sore throat, and cough. The condition gradually worsens, with the body temperature rising stepwise to 39 to 40℃ within 5 to 7 days. Before fever, there may be chills but not severe shivering, and sweating is not significant when the fever subsides.

　　2. The extreme stage.During the 2nd to 3rd week of the disease course, the typical manifestations of typhoid fever are often present, which are helpful for diagnosis.

　　(1) High fever: Continuous high fever without abatement, with most (50% to 75%) presenting as a稽留热 type, a few as a弛张热 type or irregular type, lasting about 10 to 14 days.

　　(2) The symptoms of the digestive system are more obvious, with the tip and edge of the tongue being red and the coating thick and greasy (i.e., the so-called typhoid tongue), abdominal discomfort, distension, and constipation in most cases, while diarrhea is the main symptom in a few cases. Since intestinal diseases often occur at the end of the ileum and the ileocecal junction, mild tenderness may be present in the lower right abdomen.

　　(3) The symptoms of the nervous system are proportional to the severity of the disease, caused by the action of Salmonella typhi endotoxin on the central nervous system. Patients may show confusion, indifference, apathy, dull reactions, decreased hearing, and in severe cases, delirium, coma, or meningeal irritation signs (pseudo-menigitis). These symptoms of the nervous system usually gradually recover as the body temperature decreases.

　　(4) Relative bradycardia (20% to 73%) is often present in the circulatory system symptoms, or tachycardia may occur sometimes, which is one of the clinical characteristics of the disease. However, relative bradycardia is not obvious when complicated with toxic myocarditis.

　　(5) Splenomegaly begins on the sixth day of the disease course, and an adenoma can often be felt under the left costal margin (60% to 80%), soft in texture or with tenderness. A few patients may also have liver enlargement (30% to 40%), soft in texture or with tenderness. Severe cases may develop jaundice, and significant abnormalities in liver function suggest the presence of toxic hepatitis.

　　(6) The rash lasts for 7 to 13 days, and some patients (20% to 40%) develop faint red macules (rose spots) on the skin, with a diameter of about 2 to 4 mm, which fade under pressure. There are fewer than 12 spots, appearing in batches, mainly distributed in the chest and abdomen, also seen on the back and limbs, and usually disappear within 2 to 4 days. Crystal-like sweat rash (or called white freckle) is also not uncommon, and it often occurs in those who sweat more.

　　3. Remission period.It corresponds to the third to fourth week of the disease course, when the body's resistance to Salmonella typhi gradually increases, the body temperature fluctuates and begins to decline, appetite gradually improves, abdominal distension gradually disappears, and the spleen begins to shrink. However, there is a risk of intestinal hemorrhage or perforation during this period, and special vigilance is required.

　　4. Recovery period.It corresponds to the fourth week of the disease course, when the body temperature returns to normal, appetite improves, and general recovery to health occurs within about a month.

　　II. Other clinical types

　　In addition to the typical typhoid fever mentioned above, typhoid fever can be divided into the following types according to factors such as age of onset, body immune status, virulence and quantity of pathogenic bacteria, irregular application of antimicrobial drugs in the early stage of the disease, and the presence or absence of complications.

　　1. Mild type.The systemic toxic blood symptoms are mild, the course of the disease is short, and recovery occurs within 1 to 2 weeks. It is often seen in patients who have received typhoid vaccine before onset or have been treated with effective antimicrobial drugs at the early stage of the disease. It is not uncommon in children. Due to the mild condition and atypical symptoms, it is easy to miss or misdiagnose the disease.

　　2. Fulminant type.The onset is acute, with severe toxic blood symptoms, including chills, high fever, abdominal pain, diarrhea, toxic encephalopathy, myocarditis, hepatitis, intestinal paralysis, shock, and so on. There are often significant rashes, and disseminated intravascular coagulation (DIC) may also occur.

　　3. Protracted type.The onset is similar to typical typhoid fever. Due to the low body immune function, fever persists and can last for 45 to 60 days. Patients with chronic schistosomiasis complicated with typhoid fever often belong to this type.

　　When typhoid fever is complicated with schistosomiasis, the onset is often acute, fever is often remittent or intermittent, liver and spleen enlargement is prominent, eosinophils significantly decrease or disappear during the fever and peak periods, and after the fever subsides, they often rise above the normal value, and the fever course can last for 1 to 2 months.

　　4. Children's typhoid.The older the age, the more the clinical manifestations resemble those of adults, and the younger the age, the less typical the symptoms.

　　Symptoms of children in the school age are similar to those of adults, but they are mostly mild, often acute onset, with persistent fever, loss of appetite, abdominal pain, constipation, apathy, drowsiness, irritability, epistaxis, thick tongue fur, abdominal distension, and enlargement of the liver and spleen. Slow pulse and rose spots are rare, white blood cell count usually does not decrease, the course of the disease is short, and sometimes it can recover naturally in 2 to 3 weeks. Since the intestinal lesions are light, complications such as intestinal hemorrhage and intestinal perforation are also rare.

　　Infantile typhoid fever is often atypical, and the course is also light or severe. It starts suddenly, accompanied by vomiting, convulsions, irregular high fever, rapid pulse, abdominal distension, diarrhea, etc. Rose spots are rare, the white blood cell count is often increased, and it is common to have complications such as bronchitis or pneumonia.

　　5. Elderly patients with typhoid fever often have no high fever, the symptoms are not typical, and the weakness is obvious. They are prone to complications such as bronchopneumonia and heart failure. There are often persistent intestinal dysfunction and memory loss, the course is protracted, recovery is difficult, and the mortality rate is high.

　　Relapse and recurrence: 1-2 weeks after the symptoms disappear, the clinical manifestations are similar to the initial attack. The positive blood culture is relapse, which is less severe and shorter in course, related to the large-scale reproduction of latent bacteria in the gallbladder or reticuloendothelial system, and re-invasion into the blood circulation. It is more common when the course is insufficient and the body's resistance is low, and it can relapse 2-3 times occasionally. Relapse refers to the recurrence of fever during the course of the disease, which rises again during the gradual decline of body temperature, and returns to normal after 5-7 days. The blood culture is often positive, and the mechanism is similar to the primary onset.

　　The prevention of typhoid and paratyphoid fever lies in paying attention to dietary hygiene and controlling the key of 'disease entering through the mouth':

　　1. Do not eat seafood such as clams, oysters, and scallops raw or semi-raw.

　　2. Do not dine at stalls or restaurants with poor hygiene conditions.

　　3. Develop good hygiene habits, do not drink unboiled water, and wash hands before meals and after defecation.

　　4. Any patient with persistent fever of unknown cause should be diagnosed and treated in a timely manner to avoid delaying the disease.

　　5. When there are typhoid fever patients at home or around, more attention should be paid to self-protection, and disinfection can be chosen by boiling or soaking in disinfectant for items that may be contaminated.

　　6. Emergency prophylactic medication, you can use 2 tablets of复方新诺明, twice a day, for 3-5 days.

　　7. Emergency vaccination: The key population in the outbreak area and adjacent areas should be vaccinated with typhoid vaccine as a preventive measure.

　　What kind of examination should be done for typhoid and paratyphoid fever? Briefly described as follows:

　　First, routine examination

　　The blood leukocyte count is mostly 3×109/L to 4×109/L, accompanied by decreased neutrophils and disappearance of eosinophils. The latter recovers gradually with the improvement of the condition, and eosinophils >2% can basically exclude typhoid fever. There may be slight proteinuria during high fever, and the fecal occult blood test is positive.

　　Second, bacteriological examination

　　1. Blood culture. It is evidence for diagnosis, which can be positive in the early stage of the disease. The positivity rate can reach 90% from the 7th to 10th day of the disease, and decreases to 30% to 40% in the third week, and often negative in the fourth week;

　　2. Bone marrow culture. The positivity rate is higher than that of blood culture, especially suitable for those who have been treated with antibiotic drugs and have negative blood cultures;

　　3. Fecal culture. Positive cultures can be obtained from the incubation period, and can reach up to 80% in the 3rd to 4th week. The positivity rate rapidly decreases in the 6th week after the disease, and 3% of patients may shed bacteria for more than a year;

　　4. Urine culture. The positivity rate can reach 25% in the late stage of the disease, but it should be avoided to contaminate with feces;

　　5. Scrapings or biopsy slices of roseola can also yield positive cultures.

　　Three, immunological examination

　　1, Widal test typhoid serum agglutination test

　　That is, the Widal reaction is positive, which has auxiliary diagnostic value for typhoid and paratyphoid fever.

　　2, Other immunological tests

　　(1) Passive Hemagglutination Test (PHA).

　　(2) Agglutination Immunoelectrophoresis (CIE).

　　(3) Coagulation Agglutination Test (COA).

　　(4) Immunofluorescence Test (IFT).

　　(5) Enzyme-linked Immunosorbent Assay (ELISA).

　　Four, molecular biological diagnostic methods

　　1, DNA Probe (DNAProbe).

　　2, Polymerase Chain Reaction (PCR).

　　What are the key points for dietary health care for typhoid and paratyphoid fever patients? The introduction is as follows:

　　First, eat

　　1, Give high-calorie, high-vitamin, easy-to-digest residue-free diet. During the fever period, it is advisable to use liquid or soft residue-free diet, and eat in small and frequent meals.

　　2, When typhoid patients are recovering, their appetite will increase significantly. At this time, you should endure it to avoid recurrence of the disease. You should eat less and more meals, and choose easily digestible high-protein foods, such as scrambled eggs mixed in a bowl and steamed, milk, meat soup, and meat floss are all good, green vegetables, fruits, and fried foods should be avoided, and fruits should be juiced for consumption.

　　3, Drink soup made with winter melon, remember to absolutely avoid eating congee when the fever subsides, and wait for three days after the fever subsides before eating congee.

　　4, Eat more foods that can enhance immunity, such as mushrooms, mushrooms, black fungus, silver ear, etc.

　　Second, avoid eating

　　1, Do not eat vegetables raw. People who like to eat raw vegetables such as coriander, mint, and houttuynia should be disinfected or cooked before eating.

　　2, Do not drink raw water and do not eat decayed and deteriorated food.

　　3, During the epidemic season, try to eat less or no cold food, such as cold rice noodles and cold rice rolls.

　　4, Avoid hard foods, foods with a lot of residue and rough fibers, and刺激性食物 such as sprouts, celery, chives, chili, pepper, mustard and strong alcohol, as these foods can mechanically stimulate the intestinal wall after entering the gastrointestinal tract, easily induce bleeding and perforation, or stimulate the gastrointestinal tract, causing the mucosa to become congested, worsening the condition.

　　5, Avoid eating foods that produce a lot of gas such as sweet potatoes and potatoes, as these foods can exacerbate intestinal bloating and worsen the condition.

　　Three, typhoid food therapy prescription

　　1, Shaoyao and Tangerine Peel Drink: Fresh hawthorn 500 grams, tangerine peel, green peel, amomum, pomegranate, wumei each 10 grams, sugar to taste. Wash the hawthorn, cook and remove the seeds, then grind into a paste. Add sugar to the various herbs and boil in 1000 milliliters of water for 30 minutes, then filter the juice and remove the residue. Take twice a day, as a tea drink.

　　It can regulate Qi and soothe the liver, strengthen the spleen and stop diarrhea. It is suitable for patients with liver depression and Qi stagnation type typhoid.

　　Wumei honey paste: 500 grams of wumei, 1000 grams of honey.

　　Wumei should be soaked in cold water first to remove the seeds, then add an appropriate amount of water, boil with high heat first, then simmer with low heat. Take the decoction every 20 minutes, add water and continue to boil, a total of 3 times; mix the decoctions and simmer with low heat until it becomes a thick paste. Add honey and boil after mixing in, then turn off the heat, cool and store in bottles for later use. Take 2-3 times a day, one spoonful each time, served with boiling water, for 8-10 days. It is used for poor appetite, spleen-invigorating and diarrhea-relieving.

　　3. Pomegranate peel honey syrup: 100 grams of fresh pomegranate peel (500 grams of dried), 300 grams of honey.

　　Wash the rind of pomegranate, chop it, and boil it in water. Take the decoction every 30 minutes, add water and boil again, taking the decoction twice in total. Combine the decoctions and simmer over low heat until thickened, add honey, stop boiling when it boils, cool it down, and pour it into bottles for use. Take 1 tablespoon per day, twice a day, and use boiling water to dilute it before taking, taking it for 7-10 days. It can regulate qi and soothe the liver, suitable for spleen deficiency and liver depression type of typhoid fever.

　　4. Wu梅 soup: 5-6 Wu梅, boil into a strong decoction, drink on an empty stomach before meals, with both preventive and therapeutic effects.

　　5. Boiled Portulaca oleracea: 60-90 grams of Portulaca oleracea (double the amount for fresh), 10-12 grams of dolichos lablab flower, boil and add brown sugar, take twice a day. Alternatively, dry the Portulaca oleracea, grind it into fine powder, and take with sugar, 6g per time, twice a day.

　　How is typhoid and paratyphoid fever treated in Western medicine? The introduction is as follows:

　　Clinical types of treatment

　　The treatment method varies according to the clinical type. For enteritis type, antibacterial drugs can be administered for 3 to 5 days; while for typhoid type with extraintestinal invasion, chloramphenicol is the first choice for pathogen treatment, 2550mg/kg body weight per day, taken in divided doses, with a course of treatment of at least 2 weeks. It can also be used until the body temperature returns to normal, then stop the medicine for 5-7 days, and then use the full or half dose for another 5-7 days, with a total course of treatment not less than 2 weeks. Effective patients will have bacteria cleared from the blood within a few hours after taking the medicine, sepsis improved within 2-3 days, followed by a gradual decrease in body temperature, with an average antipyretic time of about 100 hours. This drug does not help in reducing relapse and carrier state. Side effects of chloramphenicol should be paid attention to during the medication period. Ampicillin can be administered at a dose of 60-100mg/kg per day, or co-trimoxazole (co-SMZ-TMP) can be used as an alternative to chloramphenicol, with a course of treatment also exceeding 2 weeks, with slightly poorer effects than chloramphenicol. Quinolone drugs can be used for multidrug-resistant strains, such as norfloxacin (flumequine) 1.2-1.6g per day for adults or ofloxacin (fleroxacin) 600mg per day for adults; children should not use these drugs. These drugs achieve bactericidal effects by inhibiting bacterial DNA gyrase, have good oral absorption, wide distribution in the body, and are easy to penetrate into various tissues. Side effects are mild, with occasional dizziness, rash, or anorexia. Rifampicin, fosfomycin, aminoglycosides, and third-generation cephalosporins can also be used, but none are the first choice of drugs. For septicemia type, a long course of treatment of 10 to 14 days is required. Patients should rest in bed, be isolated according to enteric infectious diseases, and pay attention to water and electrolyte balance. Feverish patients can be treated with physical降温. To prevent gastrointestinal perforation, a nutritious diet should be eaten, avoiding roughage and gas-forming foods, and enema can be used for constipation. Severe patients can receive a small amount of fresh blood transfusion. Patients with intestinal bleeding should rest in bed absolutely, refrain from eating or consume liquid food, and pay attention to maintaining blood volume. Patients with intestinal perforation should reduce intestinal motility and place gastroenteric decompression. Antimicrobial therapy should not only target the typhoid bacillus but also consider intestinal bacteria and anaerobic bacteria, and pay attention to anti-shock and systemic supportive treatment. If conditions permit, surgical treatment can also be adopted, mainly focusing on simple suture and drainage.

　　For patients with severe toxic symptoms such as toxic myocarditis and toxic encephalopathy, adrenocorticosteroids can be used for 2-3 days in conjunction with sufficient and effective antibacterial drug treatment. For patients with schistosomiasis, praziquantel can be used for treatment.

　　Carriers should not engage in contact with cooked food. Quinolones or ampicillin can be used for treatment, with a course of 4-6 weeks. For those with gallbladder lesions, gallbladder resection can be considered.

　　Second, pathogen treatment

　　Select appropriate antibacterial agents.

　　1. For patients with normal blood count, liver, and kidney function infected with non-drug-resistant strains, chloramphenicol, bismuth subsalicylate, gentamicin, ampicillin, flucloxacillin, and other auxiliary drugs can be selected.

　　2. For patients with normal blood count, liver, and kidney function infected with drug-resistant strains, ampicillin, gentamicin, flucloxacillin, or ceftriaxone, cefotetan, and other auxiliary drugs can be selected.

　　3. For pregnant women with typhoid fever, children with typhoid fever, low blood count, and poor liver and kidney function, ampicillin, ceftriaxone, cefotetan, and other auxiliary drugs can be selected.

　　4. For patients with typhoid fever complicated with intestinal hemorrhage or perforation, antibiotics should be used in combination, and comprehensive treatment should be strengthened for symptomatic support.

　　5. For chronic carriers, effective antibacterial drugs should be used in combination, with sufficient dosage and long course of treatment, and special drugs should be used for the treatment of concurrent diseases.

　　Third, treatment of complications

　　1. Treatment for intestinal hemorrhage: strengthen anti-infection and hemostasis, transfuse blood if the bleeding is severe, and consider surgery if hemostasis is ineffective;

　　2. Treatment for intestinal perforation: strengthen anti-infection, correct water and electrolyte disorders, perform gastrointestinal decompression, and choose surgery according to specific conditions.

　　Fourth, symptomatic supportive treatment

　　Refers to the treatment of high fever, severe toxic blood symptoms, abdominal distension, diarrhea, and constipation.