Clonorchis sinensis - Complication, Prognosis, Laboratory Diagnosis, Treatment, Prevention, Control

Complications of Clonorchis sinensis

Complications of Clonorchis sinensis include:

• Recurrent pyogenic cholangitis

• Cholangiocarcinoma

Recurrent pyogenic cholangitis

• most frequent complication

• caused by a partial obstruction of bile ducts by adult Clonorchis sinensis or due to secondary bacterial infections

• an acute condition observed within 1 to 3 hours after a heavy meal – caused due to excessive secretion of pancreatic juice into a partially obstructed bile duct

Cholangiocarcinoma

• a cancerous condition

• observed in patients with severe and prolonged Clonorchis sinensis infection

Prognosis of Clonorchis sinensis

Although the prognosis is good in light and acute infections, the prognosis of Clonorchis sinensis after complications such as cholangiocarcinoma is bad.

Laboratory diagnosis of Clonorchis sinensis

The laboratory diagnosis of Clonorchis sinensis is based on the detection of flask-shaped eggs in the faeces or in duodenal contents. It is done following procedures:

Samples

• Stool

• biopsy tissue (liver, pancreas)

• aspirates (duodenum)

Microscopy

• the concentration of samples can be done by the formalin-ether sedimentation method

• stool microscopy is often followed by the evaluation of worm load by enumeration of the eggs in the faecal smear

• examination of duodenal contents/fluid has more sensitivity than stool examination

• however, Clonorchis sinensis eggs are difficult to distinguish from Heterophyes, Opisthorchis, Metagonimus

Immunodiagnosis

Detection of antibodies

Since Clonorchis sinensis induces immune response i.e. presence of circulating antibodies, serological methods can be used for laboratory diagnosis.

Serological tests used to detect serum antibodies include:

• Complement fixation test

• Indirect haemagglutination test

• ELISA (double sandwich ELISA)

Skin Test

The intradermal skin test for Clonorchis sinensis infection is a simple and reliable test:

Procedure for immediate hypersensitivity test

• soluble extract of the adult Clonorchis sinensis parasite is intradermally injected (0.1ml) in one arm

• an equal volume of normal saline is injected intradermally on the other arm as a control

• development of a large wheel, pseudopodium, and erythema indicates infection

It is used for epidemiological studies rather than as a diagnostic method.

Treatment of Clonorchis sinensis

Drugs of choice for the treatment of Clonorchis sinensis infection is Praziquantel. Antibiotics are also administered to prevent recurrent pyogenic cholangitis.

In some cases of biliary tract obstruction, surgery is done to mechanically remove the adult flukes.

Prevention, Control of Clonorchis sinensis

The control and prevention of Clonorchis sinensis can be obtained by following steps:

• avoid consumption of raw, undercooked, salted, pickled, dried freshwater fish

• use of manure instead of human faeces in fish husbandry

• immediate treatment of infections in dogs, cats, and people

• use of molluscicides to control snails

• reduce contamination of water sources by animals, and human faeces i.e. proper sewage disposal