Clonorchis sinensis, commonly known as hepatic trematode, was first found in the bile duct of an overseas Chinese in Kolkata, India, in 1874, and was confirmed in China in 1908.It is mainly distributed in China, Japan, North Korea, South Korea, Vietnam and other Asian countries.There are 26 provinces, autonomous regions and special administrative regions in China with the occurrence or prevalence of the disease.It is due to bad eating habits that lead to infection.Guangdong Province in China has the largest number of infected people, with more than 5 million accounting for half of the total number of infected people in the country.Adult worms parasitize in the biliary system and cause clonorchiasis of biliary tract.
Visiting department
internal medicine
Multiple population
General susceptibility
Common causes
Adult Clonorchis sinensis parasitizes in the biliary system
Clonorchiasis is mainly distributed in Asia, such as China, Japan, Korea, Vietnam and Southeast Asian countries.In China, except Qinghai, Ningxia, Inner Mongolia, Tibet, etc., which have not yet been reported, the rest 25 provinces, cities, and autonomous regions have epidemic in varying degrees.
The prevalence of clonorchiasis sinensis is closely related to many factors, such as local residents' eating habits, in addition to having suitable first and second intermediate hosts and final hosts.
1. Infectious source
Patients, infected persons, infected domestic animals and wild animals that can excrete and suck eggs of Chinese ramus can all be regarded as the source of infection.The main host hosts are cats, dogs and pigs.In addition, it is also reported that rats, martens, foxes, wild cats, badgers and otters are also insect conserving hosts.In the laboratory, guinea pigs, rabbits, rats, nutria, hamsters and other mammals can be infected with Clonorchis sinensis
Clonorchis sinensis has a wide range of host, and its infection rate and degree are higher than human infection, which is potentially threatening to the population.
2. Transmission channels
After passing through the first intermediate host (freshwater snails) and the second intermediate host (freshwater fishes and shrimps), the eggs of the worm sucking on the Chinese branchial testes develop into metacercaria. After ingestion, the live metacercaria is activated by bile, and the larvae in the cyst break through the cyst wall, enter the hepatic bile duct through the common bile duct, and develop into adults. They can also reach the liver through blood vessels or through the intestinal wall, and finally parasitism develops into adults in the hepatic bile duct.The life span of adults is generally 20-30 years. They mainly live in the liver and bile ducts of humans, dogs, cats and pigs. When there are many worms, they can also migrate to larger bile ducts or even gallbladder, and occasionally adults can be found in pancreatic ducts.
3. Susceptible people
Clonorchis sinensis infection has no gender, age and race, and is generally susceptible to the population.The key factor of prevalence is whether the local people have the habit of eating raw or half raw fish.When cooking, roasting, scalding or steaming the whole fish, it may fail to kill all metacercaria due to insufficient temperature, insufficient time or too thick fish meat.The mode of adult infection is eating raw fish. For example, people in Guangdong Pearl River Delta, Hong Kong, Taiwan and other places are mainly infected by eating raw fish, raw fish porridge or hot fish slices;Northeast Korean residents are mainly infected by eating raw fish with wine;The infection of children is related to their eating of fish and shrimp that are not fully barbecued in the wild.
In addition, people may also be infected if they do not wash their hands or pick up fish in their mouth after catching fish, use knives and cutting boards that have cut raw fish to cut cooked food, and use utensils that have served raw fish to serve cooked food.
clinical manifestation
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There are no obvious clinical symptoms in the case of mild infection. In the case of severe infection, the main symptoms in the acute phase are anaphylaxis and gastrointestinal discomfort, including fever, stomach pain, abdominal distention, anorexia, limb weakness, pain in the liver area, and obvious increase of eosinophils in blood tests. However, most patients have no obvious symptoms in the acute phase.Most of the cases seen clinically are in the chronic phase, and the symptoms of patients often appear gradually after several years. Generally, the symptoms of the digestive system are the main symptoms, and fatigue, upper abdominal discomfort, anorexia, greasy aversion, dyspepsia, abdominal pain, diarrhea, liver pain, dizziness, etc. are common.
The common signs are hepatomegaly, mostly in the left lobe, soft, with mild tenderness, and splenomegaly is rare.Severe infection is accompanied by dizziness, emaciation, edema and anemia, which can cause cirrhosis, ascites and even death in the late stage.Children and adolescents infected with Clonorchis sinensis often have severe clinical manifestations and high mortality.In addition to gastrointestinal symptoms, there are often malnutrition, anemia, edema, hepatomegaly and developmental disorders.
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1. Etiology inspection
The diagnosis is based on the finding of eggs aspirated by the Chinese testis through fecal examination. Generally, eggs can be found in the stool one month after infection. The common methods are as follows:
(1) Smear methodAlthough the direct smear method is simple, the detection rate is not high due to the small amount of feces used, and the eggs are very small, so it is easy to miss diagnosis.The quantitative transparent method (Kato Katz, glycerin paper thick smear transparent method) is considered to be one of the most effective fecal detection methods in the large-scale investigation of intestinal parasites, which can be used for qualitative and quantitative inspection of eggs.
(2) Egg collecting methodThe detection rate of this method is higher than that of direct smear method.Egg collecting methods include floating egg collecting method and sedimentation egg collecting method, and sedimentation egg collecting methods are commonly used as water washing centrifugal sedimentation method and ether sedimentation method.
(3) Duodenal drainage bile examinationThe eggs can also be found by draining bile for centrifugation sedimentation.The detection rate of this method is close to 100%, but the technology is complex, which is difficult for general patients to accept.When the patients are treated with bile drainage clinically, there are also living worms with smooth surface and wriggling. According to the morphological characteristics, they can be used as the basis for diagnosis.
2. Immunological examination
In recent years, with the development and application of enzyme, isotope, biotin and colloidal gold labeling technologies and new methods, immunological methods have been widely used in clinical auxiliary diagnosis and epidemiological investigation.The commonly used methods are indirect hemagglutination test (IHA), indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), etc.
3. Imaging examination
When the patients with clonorchiasis sinensis were examined by B-mode ultrasound, a variety of abnormal changes could be seen on the ultrasound image, such as thick and uneven light spots in the liver, spots, lumps or snowflakes, diffuse small and medium-sized bile ducts with different degrees of expansion, rough and thickened bile duct walls, echo enhancement or bile duct proportion disorder and dead branch echo.Although the specificity of sonogram is not strong, it still has certain diagnostic value compared with epidemiology, clinical manifestations and laboratory tests.
CT examination is also of great value in the diagnosis of Chinese branch orchitis.
treatment
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Praziquantel and albendazole are the most commonly used drugs for the treatment of clonorchiasis.
prevention
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Clonorchiasis is caused by eating fresh water fish and shrimp containing metacercaria raw or half raw. To prevent clonorchiasis, we should focus on oral transmission. Preventing the ingestion of live metacercaria is the key to prevent the disease.Do not eat raw fish or undercooked fish or shrimp, improve cooking methods and eating habits, and pay attention to separate use of raw and cooked cooking utensils.Domestic cats and dogs, such as those with positive stool test, should be treated. Do not feed animals such as cats and dogs with uncooked fish and shrimp to avoid infection.Strengthen stool management.Clean the pond mud or use drugs to kill snails in combination with agricultural production.
