Opisthorchiasis
Meaning of opisthorchiasis: For the purposes of this Statement of Principles, opisthorchiasis means an infestation of the biliary system by the trematodes (parasitic flatworms) Opisthorchis felineus or Opisthorchis viverrini.
Reasonable Hypothesis (RH) — Statement of Principles No. 21 of 2025
At least one of the following factors must as a minimum exist before it can be said that a reasonable hypothesis has been raised connecting opisthorchiasis or death from opisthorchiasis with the circumstances of a person's relevant service:
- (1)ingesting the skin or flesh of raw, undercooked, iced, pickled or smoked freshwater fish at least 3 weeks before clinical onset;
Note: Freshwater fish contaminated by Opisthorchis viverrini are mainly found in Southeast Asia and freshwater fish contaminated by Opisthorchis felineus are mainly found in Eastern and Central Europe and Southeast Asia.
- (2)having a liver transplant, where the liver is derived from a person infected with Opisthorchis viverrini or Opisthorchis felineus, within the 7 days before clinical onset;
- (3)inability to obtain appropriate clinical management for opisthorchiasis before clinical worsening;
Aggravation-only factors: the factors in subsection 9(3) apply only to material contribution to, or aggravation of, the condition where it was suffered or contracted before or during (but did not arise out of) the person’s relevant service.
Balance of Probabilities (BoP) — Statement of Principles No. 22 of 2025
3 factors
At least one of the following factors must exist before it can be said that, on the balance of probabilities, opisthorchiasis or death from opisthorchiasis is connected with the circumstances of a person's relevant service:
- (1)ingesting the skin or flesh of raw, undercooked, iced, pickled or smoked freshwater fish at least 3 weeks before clinical onset;
Note: Freshwater fish contaminated by Opisthorchis viverrini are mainly found in Southeast Asia and freshwater fish contaminated by Opisthorchis felineus are mainly found in Eastern and Central Europe and Southeast Asia.
- (2)having a liver transplant, where the liver is derived from a person infected with Opisthorchis viverrini or Opisthorchis felineus, within the 7 days before clinical onset;
- (3)inability to obtain appropriate clinical management for opisthorchiasis before clinical worsening;
Aggravation-only factors: the factors in subsection 9(3) apply only to material contribution to, or aggravation of, the condition where it was suffered or contracted before or during (but did not arise out of) the person’s relevant service.
