Clonorchis sinensis

Introduction to clonorchiasis Clonorchiasis is a parasitic disease caused by Clonorchissinensis parasitic in the human intrahepatic bile duct. Humans are often infected by eating freshwater fish or shrimp that are not cooked with C. sinensis. Patients with mild infection may be asymptomatic, and those with severe infection may have clinical manifestations such as indigestion, epigastric pain, diarrhea, lack of energy, and hepatomegaly. In severe cases, complications such as cholangitis, gallstones, and cirrhosis may occur. Children with severe infections often have significant malnutrition and growth and developmental disorders. The disease is distributed all over the world, and it is popular in 24 provinces, municipalities and autonomous regions such as Guangdong, Shandong and Henan. basic knowledge The proportion of sickness: 0.002%-0.003% Susceptible people: no specific population Mode of infection: fecal-mouth transmission Complications: biliary tract infection cholangitis cholelithiasis

Causes of clonorchiasis

Parasitic infections (40%):

Clonorchis sinensis is a hermaphroditic trematode. Its life history is complex, according to the developmental procedure can be divided into eight stages of adult, egg, donkey, cellulite, thunder, scorpion, cystic scorpion and larvae. Adults are parasitic in the intrahepatic biliary system, especially in the branches of the bile duct. Even in the pancreatic duct. Adult worms are long and narrow, flat and thin at the front end, and the back end is relatively blunt and round like a sunflower seed. The surface has no spines and is brown and translucent. The size is (10 ~ 25) mm × (3 ~ 5) mm, there are two suction cups, mouth and abdomen, digestive organs have mouth, pharynx, esophagus and branch of the intestine. The reproductive organs are hermaphroditic, and both testicles are branched and arranged in the front and rear of the worm.

Bad eating habits (25%):

Humans are often infected by eating freshwater fish or shrimp that are not cooked with C. sinensis. Those who are mildly infected may be asymptomatic. Those with severe infection may have clinical manifestations such as indigestion, upper abdominal pain, diarrhea, lack of energy, and liver enlargement. In severe cases, cholangitis, gallstones, and cirrhosis may occur. Children with severe infections often have significant malnutrition and growth and developmental disorders.

Clonorchiasis prevention

Clonorchis sinensis is caused by eating freshwater fish or shrimp infected by C. sinensis cysts. The key to prevention is to cut off the route of transmission and to infect the mouth. In addition, it should Pay attention to controlling the source of infection.

1. Measures against infectious sources

(1) census and cure source: In popular areas, it is necessary to strengthen the census work, which can be screened first by skin test, positive for fecal test, and stool for positive egg test, all should be given drug treatment.

(2) Management of animal infectious sources: Cats, dogs, pigs, etc. should not be fed with raw fish, shrimp or fish viscera to avoid infection. The manure of these animals should also be managed to prevent manure from entering ditch and fish ponds, livestock. Infected persons, those who are conditionally also given deworming, and the wild animal insecticide hosts are killed according to the situation.

2. Measures against the route of transmission

(1) Do not eat uncooked fish and shrimp: Strengthen health publicity and education work, make the residents of the epidemic areas a household name, everyone understand the harmfulness of the disease and its transmission route, do not eat uncooked fish or shrimp, is The most effective measures to prevent this disease, the experiment proved that the 1mm thick fish containing cystic sputum is put into hot water of 98 °C, and it will die after 1s capsule, and it will die at 70 °C for 5s; if the fish containing capsules is thick 2~ 3mm, in water at 70 °C, it takes 8s to die; therefore, the thicker the fish, the longer it takes to heat, the stronger the resistance of the capsule to the seasoning, in vinegar (about 3.36% acetic acid), it will die after 2 hours. In soy sauce (containing 19.3% of sodium chloride), it will die after 5 hours. Therefore, uncooked fish has the possibility of spreading the disease. It should be noted that kitchen chopper and chopping board must be separated from raw food, and children should not eat grilled fish. , baked fish, burned fish or raw fish.

(2) Strengthening the management of manure: Do not allow the manure without the harmless treatment to be built, or build a toilet on the fish pond or use untreated manure as a feed for fish farming.

The epidemic of clonorchiasis is relatively clear. As long as we grasp the main link of cutting off the transmission route and then control the source of infection, the prevalence of this disease can be prevented.

Complications of clonorchiasis Complications biliary tract infection cholangitis cholelithiasis

In biliary tract infections, cholangitis and cholelithiasis are the most common.

According to the analysis of inpatient medical records of 10486 cases of clonorchiasis infection and 87039 cases of trematode infection in Guangzhou, the incidence of cholelithiasis, cholangitis, cholecystitis, cirrhosis, primary liver cancer and diabetes The trematode infected were significantly higher than those without this trematode.

In the endemic areas, the virus is often infected with Clonorchis sinensis and infected with viral hepatitis. After suffering from viral hepatitis, the symptoms of digestive tract such as fatigue and anorexia will be significantly aggravated. Liver and spleen may be more prominent, and liver function is not easy to return to normal. There are often hepatobiliary infections, and the jaundice is also difficult to resolve. There are also reports of chronic viral hepatitis re-infected with Clonorchis sinensis and the disease is aggravated.

Symptoms of clonorchiasis Common symptoms Weak abdominal pain Appetite deficiency Fatigue Debilitating High fever Abdominal gastrointestinal symptoms Low heat weight loss

The incubation period is 1 to 2 months.

The disease generally begins slowly, and only a few patients with severe infections in the short term are clinically acute.

Mildly infected people are often asymptomatic or have a feeling of fullness in the upper abdomen after eating, lack of appetite or mild abdominal pain, the patient is prone to fatigue, and eggs can be detected in the feces.

Heavier infected people usually have slower onset, lack of appetite, upper abdominal fullness, mild diarrhea, and pain in the liver area. 24% to 96.3% of patients have large liver, obvious in left lobe, tenderness and snoring pain. May be associated with dizziness, insomnia, fatigue, lack of energy, palpitations, memory loss and other neurasthenia symptoms, individual patients with obstructive jaundice due to a large number of adults blocking the common bile duct, and even biliary colic.

When severe cases of chronic repetitive infection develop into cirrhosis and portal hypertension, weight loss, anemia, abdominal varices, hepatosplenomegaly, ascites, jaundice, etc. may occur, and severely infected children may develop malnutrition and growth and development disorders, and may even cause Dwarfism.

Severe infections can often present acute onset, the incubation period is short, only 15 to 26 days, patients with sudden chills and high fever up to 39 ° C, showing relaxation heat, loss of appetite, tired of greasy food, liver with tenderness, mild jaundice A small number of splenomegaly appeared, and after a few weeks, the acute symptoms disappeared and entered the chronic phase, which was characterized by fatigue, indigestion, and liver hypertonic tenderness.

Clinical severity: The symptoms of clonorchiasis vary from one to three, and can generally be divided into three degrees:

1 Mild: no symptoms, only found in the stool examination, or mild gastrointestinal symptoms, such as tenderness in the stomach after eating, soft stools, etc., accounting for about 35%.

2 moderate: mainly have obvious gastrointestinal symptoms, such as lack of appetite, indigestion, upper right abdominal pain, liver, mild edema, such as complicated bacterial infection can be secondary to cholangitis, cholecystitis, accounting for about 55%.

3 severe: obvious gastrointestinal symptoms, repeated diarrhea or constipation, right upper quadrant pain or splenomegaly, ascites, anemia, etc., more common in children, accounting for about 10%.

Clinical classification: The clinical manifestations of this disease are diverse, and the induction can be divided into eight clinical types:

1 Asymptomatic type: no symptoms, diagnosis of fecal eggs during stool examination or duodenal drainage, accounting for 16.9% to 40.13%.

2 Hepatitis type: the most common, manifested as lack of appetite, fatigue, liver pain, liver, mild tenderness, serum alanine aminotransferase (ALT) activity increased in some patients, accounting for 36.38% ~ 40.16%.

3 gallbladder cholangitis type: manifested as right upper quadrant pain, can be paroxysmal, sometimes irregular low fever or high fever, often complicated by cholecystitis or cholelithiasis, accounting for 6.83% to 11.3%.

4 gastroenteritis type: also common, manifested as abdominal distension, abdominal pain and diarrhea, stool 3 to 4 times a day, no pus and blood, may have indigestible food, accounting for 13.76% to 31.7%.

5 neurasthenia type: manifested dizziness, headache, palpitations, insomnia, multiple dreams, temperament, poor memory, etc., accounting for 2.06% to 2.3%.

6 cirrhosis type: manifested by lack of appetite, hepatosplenomegaly, ascites, anemia, hypersplenism, liver function is significantly damaged, more common in children with severe infection, accounting for 0.58% to 1.4%.

7 dystrophic type: manifested as edema, anemia, decreased plasma protein, also more common in children with severe infections, accounting for about 2.1%.

8 pygmy type: manifested as developmental disorders, height, weight and age are extremely disproportionate, lack of secondary sexual characteristics, this type is rare, can be seen in childhood and repeated infections.

The same patient may have several of the above clinical types. In addition, there are very few patients from non-endemic areas, the first time a large number of infections, sudden onset of symptoms about 1 month after infection, chills, high fever, middle and upper abdomen or right upper abdomen pain, liver with tenderness, mild jaundice, also Have splenomegaly. Eosinophils in the blood are significantly increased. Very few patients develop leukemia-like reactions. After a few weeks, the acute symptoms disappeared and there were still manifestations of indigestion, fatigue, and hepatomegaly.

Examination of clonorchiasis

Blood test

Acute patients may have increased white blood cell counts and eosinophilia. Eosinophilic leukemia may occur in severely infected patients. Leukocytes may reach 50×109/L, and eosinophils may reach 60% or more. Chronic The patient may have mild anemia, and the total number of white blood cells is normal or slightly increased. In most cases, the eosinophils increase slightly (up to 5% to 10%). As the disease progresses, the patients may have different degrees of anemia, and the white blood cell counts are mostly normal. However, eosinophilia, erythrocyte sedimentation rate, serum alkaline phosphatase, alanine aminotransferase and -glutamyl transpeptidase activity increased, total plasma protein and albumin decreased.

2. Immunological examination

(1) Detection of specific antibodies in serum:

1 Indirect erythrocyte agglutination test: It has the advantages of simple operation and rapid judgment, but its stability is not ideal. The method of antigen preparation is basically the same, but antigen extraction, antigen concentration of sensitized red blood cells, treatment of red blood cells, etc. The steps and conditions are different, and the positive rate of detection is 68.4%-98.7%, and the difference range is large.

2 enzyme-linked immunosorbent assay: it is a more used method, the sensitivity and specificity are higher, the detection antibody sensitivity is mostly 90% to 95%, the false positive rate is 1% to 5%, for paragonimiasis The sera of schistosomiasis patients have about 10% cross-reactivity.

(2) Detection of specific antigen in serum: The double-sandwich method enzyme-linked immunosorbent assay was used to detect the specific circulating antigen in the serum of patients with this disease, which is superior to the method for detecting antibody.

(3) Skin test: High-dilution antigen should be used for skin test, usually by cold soaking with adult saline solution (dilution: 1:150001:30000) for intradermal test, the positive rate can be as high as 97.9%, with feces The positive coincidence rate is as high as 99.5%. The test is simple and easy to perform, has high specificity, and has no cross-reaction with other trematode diseases. It has the value of auxiliary diagnosis and screening. The research proves that when the antigen dilution is 1:15000, The identification rate of schistosomiasis reached 100%. When diluted to 1:30000, the identification rate with Paragonimus was 97.9%, and that with Fasciola hepatica was 94.8%.

3. Parasitological examination

Mainly for stool examination, the direct smear method is easy to operate. The disadvantage is that in the case of mild infection, there are few eggs in the feces, which are difficult to detect. Usually, several smears are taken to increase the detection rate, and the method of sediment collection is available. Precipitation of clear water, because the eggs are heavier and smaller, it is suitable for this method. It can also be precipitated with clear water and then centrifuged. It can also be treated with hydrochloric acid and then centrifuged to concentrate the eggs on the tip of the glass and easily detect it. Digestion method can also be used as the egg count test method. Take 1g of feces and place it in a centrifugal sedimentation tube containing 5ml of 10% sodium hydroxide solution. Stir well, digest for 1h, stir well with a Sterling tube and draw 0.075ml. Smear, count the whole piece of eggs under the microscope, and multiply by 80, which is the number of eggs per gram of feces.

Examination of bile or duodenal juice, duodenal drainage with duodenal drainage, especially bile, the detection rate of eggs is greatly improved, because the eggs are directly discharged into the duodenum from the bile duct, in the bile The most eggs and no impurities are mixed, and it is easy to detect. The positive rate of the eggs is higher by using the whole bile sedimentation of the drainage. In addition, adults are found in biliary tract surgery, and adults are found in the biliary drainage tube. Or eggs, or adults or eggs found in the needles of the liver puncture or in the tissue block, can help to confirm the diagnosis.

When using B-mode ultrasound to examine patients with clonorchiasis, it can be seen that the intrahepatic light spots are coarse and dense, with small patches or clump-like echoes, diffuse, small bile ducts dilated, bile duct wall rough, thickened, echo Enhancement, in 1528 cases of clonorchiasis patients with B-mode ultrasound examination found 210 cases of abnormal changes of hepatobiliary system, accounting for 13.3% of the total, including 120 cases of intrahepatic small bile duct wall echo enhancement, bile duct wall thickening 25 cases, gallstone There were 22 cases, 7 cases of gallbladder foreign bodies, 3 cases of liver cancer, and 45 cases of spleen. Although the sonogram is non-specific, it still has certain reference value.

CT examination of patients with Clonorchis sinensis, the diameter of the bile duct and length ratio is less than 1:10; cystic dilated bile duct is mainly distributed around the liver, the diameter of the tube is similar, a few cases can be seen in the gallbladder irregular tissue shadow .

Diagnosis and identification of clonorchiasis

Diagnostic criteria

The diagnosis of this disease should first pay attention to the collection of medical history. Any resident in the popular area or a traveler who has visited the epidemic area, and who has a history of eating raw fish, when chronic digestive tract disorders such as abdominal distension, abdominal pain, diarrhea, can not accommodate fat diet And the symptoms of hepatobiliary diseases such as liver discomfort, that is, the possibility of the disease should be considered, and then the fecal and liver flukes are further tested in the skin. The diagnosis depends on the discovery of liver fluke eggs in the feces, and the suspected patients are negative in the fecal test eggs. , it is advisable to use the duodenal drainage fluid to find eggs.

Differential diagnosis

The disease should be diagnosed with the following diseases.

Hepatic schistosomiasis

Fasciola hepatica is parasitic on cattle, bile duct or liver of sheep. It is a parasitic disease of livestock. The doll can be eaten by aquatic plants containing this sac, or drinking raw water contaminated with sacs. Infection, its clinical manifestations are similar to those of clonorchiasis but the disease is more serious. Obstructive jaundice is more common, and it is easy to have biliary tract hemorrhage. Feces can be diagnosed in feces. More than ten cases have been reported in China.

2. Heteromorphosis

An example of a mixed infection of the clonorchiasis and Heterophyes heterophyes or a single infection of the genus Heterodera, it has been found in China that the life history of the worm is similar to that of the clonorchiasis, but the worm is mainly parasitic in the depth of the intestinal mucosa. It can invade the other organs of the human body with blood flow, causing local embolism and ectopic damage. The morphology and size of the eggs of the genus Schistosomiasis are very similar, and should be identified during the fecal examination.

3. Other trematode diseases

The eggs of Metagonis yokogawai and Opisthorchis felineus are similar to the eggs of Clonorchis sinensis, and should be identified. Yokogawa has found more than 10 cases in China. In many parts of the world, there are human cat worm infections, and the number of infected people is estimated to exceed 1 million. There are no reports of human infections in China.

4. No jaundice-type viral hepatitis

There is no history of eating uncooked freshwater fish (or shrimp), and there is a close contact with patients with viral hepatitis. The symptoms of digestive tract and the pain in the liver area are more significant. The liver is swollen and the liver function is abnormal. Hepatitis virus The serological markers were positive, and the feces were examined for C. sinensis eggs.

5. Cholecystitis

Cholecystitis caused by Clonorchis sinensis, cholangitis should be differentiated from cholelithiasis and bacterial infection caused by cholecystitis, their clinical symptoms are similar, serum immunoassay and positive fecal eggs can be clearly diagnosed.

6. Primary liver cancer

The patient is older, the liver pain is more obvious, the liver is progressively enlarged, the surface can touch the nodules and masses, the whole body is wasted, the alpha-fetoprotein is obviously increased, the ultrasound examination, the radionuclide liver scan, CT or magnetic resonance examination can be auxiliary Diagnosis, liver biopsy can confirm the diagnosis.

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