Clonorchiasis sinensis

　　Clonorchiasis is a parasitic disease caused by Clonorchis sinensis寄生 in the bile ducts of the human liver. The main causes of the disease are:
　　1. Humans and mammals infected with Clonorchis sinensis (such as cats, dogs, rats, pigs, etc.) are the main sources of infection.
　　2. Humans often become infected with Clonorchis sinensis through the digestive tract by eating freshwater fish or shrimp that are not fully cooked and contain live metacercariae. Raw fish or shrimp are the main modes of infection, and in addition, cooking methods such as roasting and frying that do not kill the metacercariae completely can also lead to infection with Clonorchis sinensis and cause disease. Cooking utensils that are not separated into raw and cooked food can also lead to infection with Clonorchis sinensis.
　　3. Humans are generally susceptible to clonorchiasis, so anyone who eats freshwater fish or shrimp containing live Clonorchis sinensis metacercariae can be infected. The differences in infection rates in different places and among different populations are mainly related to lifestyle, dietary habits, and the distribution of freshwater fish.

　　Clonorchis sinensis adults and eggs can cause obstruction of the bile ducts, plus the mechanical injury caused by the adults can cause the detachment of bile duct epithelium, which is prone to secondary bacterial infection, leading to acute cholecystitis and cholangitis, and the appearance of corresponding clinical symptoms.

　　Generally, clonorchiasis may lead to the following four complications: liver cirrhosis; liver cancer; leukemoid reaction; ectopic parasitism and ectopic damage.

　　Symptoms of acute clonorchiasis:

　　1. Incubation period: 5-40 days, usually 30 days.

　　2. Fever: the highest body temperature can reach above 39℃, often accompanied by chills and shivering. The type of fever is irregular, and the duration of fever varies.

　　3. Abdominal pain and diarrhea: most patients present with upper abdominal pain as the first symptom, resembling acute cholecystitis.

　　4. Liver pain and liver enlargement: mainly with the enlargement of the left lobe of the liver, often accompanied by marked tenderness, mainly related to intrahepatic bile duct inflammation.

　　5. Allergic symptoms: The most common are urticaria and increased acidophilic cells in peripheral blood, and in severe cases, even a leukemoid reaction dominated by acidophilic granulocytes may occur.

　　In order to effectively prevent clonorchiasis, the following 4 points should be noted:

　　Strengthen health education and publicity, improve the public's awareness of disease prevention.

　　Do not eat raw or undercooked freshwater fish or shrimp to prevent accidental ingestion of metacercariae, and control the entry of 'disease from the mouth';

　　Strengthen the management of feces, prevent the eggs from entering the water; control the source of infection, actively treat patients and carriers;

　　Appropriately control the first intermediate host: if the density of snails in fish ponds is too high, drug control of snails can be used to cut off the transmission link of clonorchiasis.

　　1. Pathogenic examination: direct fecal smearCysticercus is the smallest type of human parasitic egg, about 30 × 14 μm in size, slightly resembling the shape of a light bulb, with a thick shell, brownish yellow in color, with a small lid at the top and a small nodule at the bottom, containing a mature nematode. The sedimentation method or sodium hydroxide digestion method has a high positive rate and can be used to count the eggs at the same time. There is a higher chance of detecting eggs in duodenal drainage fluid. The detection of Clonorchis sinensis eggs can confirm the diagnosis. Egg counting helps to understand the degree of infection and the effectiveness of treatment.

　　2. Immunological examination

　　(1) Skin test: It is advisable to use high-dilution antigens for skin tests. Usually, the adult worm saline immersion is used as the antigen (dilution ratio of 1:15000 to 1:30000) for intradermal tests, with a positive rate of up to 97.9% and a high coincidence rate of 99.5% with fecal positivity. This test is simple and easy to perform, with high specificity and almost no cross-reactions with other schistosome diseases, and has the value of auxiliary diagnosis and preliminary screening in mass screening.

　　(2) Detection of specific antibodies in serum: ① Indirect hemagglutination test: It has the advantages of simple operation and rapid judgment of results, but its stability is not ideal. The methods of antigen preparation are basically the same, but the steps and conditions of antigen extraction, antigen concentration used for sensitizing red blood cells, and red blood cell processing are different. The positive rate of detection is 68.4% to 98.7%, with a wide range of differences. ② Enzyme-linked immunosorbent assay: It is a commonly used method with high sensitivity and specificity. The sensitivity of detecting antibodies is mostly 90% to 95%, with a false-positive rate of 1% to 5%. It has about 10% of cross-reactions with serum from patients with paragonimiasis and schistosomiasis.

　　(3) Detection of specific antigens in serum: The double-antibody sandwich enzyme-linked immunosorbent assay is used to detect specific circulating antigens in the serum of patients with this disease, which is significantly superior to the method of detecting antibodies for evaluating efficacy.

　　3. Blood tests Leukocyte count is elevated, and eosinophils are increased. Chronic patients may present with mild anemia. As the course of the disease extends, patients may have varying degrees of anemia. White blood cell counts are mostly normal, but eosinophils are increased, erythrocyte sedimentation rate is accelerated, and the activity of serum alkaline phosphatase, alanine aminotransferase, and gamma-glutamyl transferase is increased. Total plasma protein and albumin are reduced.

　　4. Imaging examination

　　(1) Ultrasound examination shows uneven liver light points, with small spots or mass-like echoes, diffuse moderate to small bile duct dilation of varying degrees, rough, thickened bile duct walls, and enhanced echoes.

　　(2) CT examination shows bile duct dilation, and in a few cases, irregular tissue mass shadows can be seen in the gallbladder.

　　Patients with clonorchiasis mainly manifest cholangitis, and dietary attention should be paid to nourishment. Dietary treatment can alleviate the symptoms of patients, regulate the secretion of bile, improve the composition of bile, and promote the recovery of cholangitis. The dietary principles for these patients are as follows:

　　1. Control the intake of fat: Since fat can promote the production of cholecystokinin and enhance the contraction of the gallbladder, it is advisable to limit the intake of fat. During the acute attack, patients should fast or strictly limit the intake of fat, and can be given high-carbohydrate liquid foods such as congee, fruit juice, almond tea, lotus root starch, etc. After the symptoms are relieved, the variety and amount of food can be gradually increased, with vegetable oil being preferable for fat, reducing the intake of animal oils such as lard, butter, and beef fat, and avoiding foods high in fat and cholesterol such as fatty meat, fish roe, and animal internal organs.

　　2．蛋白质按正常需要量供给：蛋白质可促进胆囊收缩，有利于胆囊排空。适量的蛋白质可以保护肝脏，修复受损的肝细胞，可进食鸡、鱼、瘦肉、兔肉等，鸡蛋以蛋清为主，减少蛋黄的摄入（每周可食用2～3个）。

　　2. Protein supply according to normal needs: Protein can promote gallbladder contraction and is beneficial to gallbladder emptying. Appropriate protein can protect the liver, repair damaged liver cells, and can eat chicken, fish, lean meat, rabbit meat, etc., with egg whites as the main ingredient, reducing the intake of yolk (2-3 eggs can be eaten per week).

　　3. Adequate intake of carbohydrates: The main source of calories.

　　4. Supplement sufficient vitamins: Patients can eat more vegetables and fruits, such as oranges, apples, tomatoes, etc. Fat restriction can affect the absorption of fat-soluble vitamins, and attention should be paid to the supplementation of vitamins A, D, E, and K.

　　The conventional method of Western medicine for the treatment of Opisthorchis viverrini disease

　　Common Dosage: Adult total dose: 210mg/kg (for body weight over 60kg, calculate as 60kg), taken orally for 3 days, 3 times a day. Or 75mg/kg.d, taken 3 times a day, for 2 days as a course of treatment.

　　Praziquantel pharmacokinetics: Rapid oral absorption, over 80% of the drug is absorbed from the intestines. The blood drug peak arrives around 1 hour. The drug is metabolized quickly after entering the liver, mainly forming hydroxyl metabolites. The concentration in the portal vein blood flow can be 10 times higher than that in the peripheral venous blood drug concentration, and the concentration in the cerebrospinal fluid is about 20%. The drug is mainly distributed in the liver, followed by the kidneys, lungs, pancreas, adrenal glands, and others. There is no organ-specific accumulation phenomenon. It is mainly excreted by the kidneys in the form of metabolites, 72% within 24 hours, and 80% within 4 days.