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Opisthorchiasis A008

Last amended 
9 May 2016
Current RMA Instruments:
Reasonable Hypothesis SOP
45 of 2016
Balance of Probabilities SOP
46 of 2016
Changes from previous Instruments:

SOP Bulletin 190

ICD Coding:
  • ICD-9-CM Codes: 121.0
  • ICD-10-AM Codes: B66.0
Brief description

Opisthorchiasis is a parasitic infection of the bile ducts by a type of liver fluke.  It is acquired by eating un- or undercooked fresh water fish from certain Asian and east European countries.

Confirming the diagnosis

The diagnosis needs to be confirmed by laboratory testing.  This involves microscopic identification of eggs in stool specimens or from duodenal aspirate.  An enzyme-linked immunosorbent assay (ELISA) method for detecting antigen in the stool may also be used.

Additional diagnoses covered by SOP

  • Nil
Conditions not covered by SOP
  • Clonorchiasis*

* another SOP applies

Clinical onset

Most infections are asymptomatic.  In mild cases, manifestations include dyspepsia, abdominal pain, diarrhea or constipation.  With infections of longer duration, the symptoms can be more severe, and hepatomegaly (enlarged liver) and malnutrition may be present.  The usual incubation period is 3 to 4 weeks.  Clinical onset can be based on the time of diagnosis, or backdated if relevant symptoms consistent with clinical infection have been present.

Clinical worsening

The only worsening factor is for inability to obtain appropriate clinical management.