What is Clonorchos?
Clonorchosis is a chronic helminthiasis with a primary lesion of the biliary system and the pancreas.
Causes of Clonorchosis
The causative agent of clonorchosis is a trematode of the family Opisthorchidae – Clonorchis sinensis (the synonym is Chinese fluke). It was first described by Ms Connéll in 1874, studied in detail by Kobajashi in 1910. The body is flat, 10-20 mm long, 2-4 mm wide. At the front end is the oral sucker, on the border of the first and second quarters of the body – the abdominal sucker. The eggs are yellowish-brown with a cap on one end and a thickening of the shell on the opposite; their sizes are 0,026-0,035 x 0,012-0,0195 mm; they are distinguished by the absence of a shoulder-like protrusion from the eggs of opisthorchiasis pathogens. Helminth in puberty is parasitic in humans and carnivorous mammals, which are definitive hosts. Freshwater mollusks serve as intermediate hosts, cyprinid fish and freshwater crayfish as additional hosts. The lifespan of the causative agent of clonorchiasis in humans up to 40 years.
Sources are infected people (mostly), cats, dogs. The helminth eggs secreted with faeces, when released into the water, are swallowed by mollusks, in the body of which, after 2 weeks, the larvae form cercariae form. Cercariae actively penetrate into the subcutaneous tissue and muscles of fish and crayfish, where they turn into metacercariae. A person becomes infected by eating insufficiently thermally treated infected fish and crayfish. Clonorchosis is widely distributed in China, Korea, Japan, in the Amur basin and Primorye.
Pathogenesis during Clonorchosis
In persons living in endemic areas, immunity develops, which is transmitted transplacentally, which causes a milder course of the disease. In the foci of clonorchosis infection occurs in early childhood and the disease is acute, remaining unrecognized. Pathogenesis is based on adenomatous proliferation of the epithelium of the bile ducts (considered as a precancerous condition), the attachment of a secondary microbial flora, the mechanical action of a helminth, toxic-allergic reactions, neurotrophic disorders.
Symptoms of Clonorchosis
The common biology and epidemiology of clonorchosis and opistrochosis pathogens determines the similarity of the clinical manifestations of both helminthiasis. In non-immune persons who have arrived at the center, the disease proceeds according to the type of acute allergy (malaise, high fever, enlarged liver, rarely spleen, lymphadenitis, eosinophilia, sometimes up to 80%), subcultured sclera can occur. After 2-4 weeks, the acute manifestations subside, and at the same time the clonorchis eggs appear in the feces of the patients. In the later stages, the disease manifests manifestations of angiocholitis, biliary dyskinesia, chronic hepatitis and pancreatitis, and in far advanced cases cirrhosis of the liver may develop (against the background of cholangitis or massive obstruction of the common bile duct). The course of the disease is chronic, with occasional exacerbations.
Diagnosis of Clonorchosis
Laboratory methods of research play a leading role in the diagnosis of clonorchosis, however, data from the clinic and patient survey are also important (staying in areas unfavorable for clonorchosis, eating insufficiently processed fish). In the clinical analysis of blood marked eosinophilia (increase in the number of eosinophils).
During periods of exacerbations during biochemical research, an increase in the level of bilirubin and a moderate violation of the protein composition of the blood are determined. Specific diagnostics is carried out using serological tests for the detection of Chinese pig eggs in the contents of the duodenum and in feces. Differential diagnosis of opisthorchiasis and clonorchiasis is possible only by the results of laboratory studies.
Clonorchosis treatment is carried out:
- biltricid (20-60 mg / kg per day in 1–3 doses, course is 1 day, taken one hour after a meal, efficacy 80–90%);
- hloksilom (60 mg per kg of body weight per day in 3 doses, the course – 5 days, 15-20 minutes after a meal, drink milk, efficiency – 75%).
Good results were obtained in the treatment of nicofolan at a dose of 1-2 mg / kg body weight for 2-3 days.
The prognosis for clonorchosis is usually favorable.
Prevention of Clonorchosis
Of great importance is the protection of waters from faecal pollution, as well as sanitary-educational work, the purpose of which is to convince the population not to use raw and half-salted fish. Metacercariae die when cooking fish in 20 minutes. Hot smoking completely disinfects the fish. Fry fish should be plastovannoy 15-20 minutes. Salt the fish for 14 days, salt consumption 27-29 kg per 100 kg of fish, its content in the finished product is not lower than 14%. Disinfection of infested fish by freezing under natural conditions and with an ice-salt mixture is not recommended, since metacercariae remain in this case for up to 2-4 weeks.