History of Opisthorchis viverrini infection (positive stool ova / microscopy, positive se...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-OPISTHORCHIS-CHOLANGIO-PREVENTION`
Type	Red flag
Status	reviewed 2026-05-18 \| pending_clinical_signoff
Diseases	`DIS-CHOLANGIOCARCINOMA`
Sources	`SRC-IARC-MONO-100B-2012` `SRC-NCCN-HCC-2025`

Red Flag Origin

Definition	History of Opisthorchis viverrini infection (positive stool ova / microscopy, positive serology, or documented endemic-region exposure with raw / undercooked freshwater-fish consumption) in an individual without a current cholangiocarcinoma diagnosis. IARC Group 1 carcinogen (O. viverrini) — established etiological driver of intrahepatic cholangiocarcinoma in the Mekong basin (Northeast Thailand, Laos, Vietnam, Cambodia). Praziquantel cures active infection but does NOT reverse chronic biliary-tract inflammation / fibrosis from prior burden; lifelong hepatobiliary surveillance (liver US + CA 19-9 every 12 months from age 40 in heavily-exposed cohorts) is the dominant prevention modality. Prevention-persona RedFlag (§20 ratification 2026-05-18).
Clinical direction	investigate
Category	other

Trigger Logic

{
  "any_of": [
    {
      "finding": "opisthorchis_viverrini_history",
      "value": "positive"
    },
    {
      "finding": "opisthorchis_viverrini_ova_stool",
      "value": "positive"
    },
    {
      "finding": "opisthorchis_viverrini_serology",
      "value": "positive"
    }
  ],
  "type": "lab_value"
}

Notes

Prevention-persona RedFlag for O. viverrini-driven cholangiocarcinoma prevention. Fires on any documented exposure history with confirmatory testing. Engine routes to PreventionPlan recommending praziquantel (if active infection) + lifelong hepatobiliary surveillance (US + CA 19-9 q12mo from age 40 in heavily-exposed cohorts). STUB pending Co-Lead review. Cancer scope: anchored to DIS-CHOLANGIOCARCINOMA. Northeast Thailand has the world's highest cholangiocarcinoma incidence (up to 90 per 100K) — attributable fraction in endemic regions exceeds 50%. Geographic context: relevant for Mekong-region diaspora, refugees, travelers, and adoptees. Companion to RF-CLONORCHIS-CHOLANGIO-PREVENTION (East Asian liver-fluke pathway, biologically similar mechanism).

Used By

Indications

IND-OPISTHORCHIS-CHOLANGIO-PREVENTION-OBSERVATION - IND-OPISTHORCHIS-CHOLANGIO-PREVENTION-OBSERVATION
IND-OPISTHORCHIS-CHOLANGIO-PREVENTION-TREATMENT - IND-OPISTHORCHIS-CHOLANGIO-PREVENTION-TREATMENT

Red flag

RF-CLONORCHIS-CHOLANGIO-PREVENTION - History of Clonorchis sinensis infection (positive stool ova / microscopy, positive serol...