Metagenomic next-generation sequencing as an adjunctive diagnostic tool for Clonorchis sinensis infection: a case report

Clonorchis sinensis is a foodborne liver fluke. This case highlights acute cholangitis in a non-endemic area, where raw-fish history was initially absent and identified only after multidisciplinary team (MDT) discussion. Conventional tests were negative. A 53-year-old female had fever, epigastric pain, leukopenia, elevated C-reactive protein (CRP) and liver enzymes, and progressive eosinophilia (6.3% to 19.7%). Abdominal computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) showed cholangitis. Plasma and stool metagenomic next-generation sequencing (mNGS) detected C. sinensis (4 and 3375 reads), prompting stool microscopy that confirmed characteristic eggs. This complementary strategy enabled timely praziquantel, with resolution of fever and abdominal pain, declining eosinophilia, and improved liver function. She was discharged on day 16 and asymptomatic at 30-day follow-up. Clonorchiasis should be considered in eosinophilic cholangitis even in non-endemic areas; mNGS is a valuable complementary tool when conventional tests fail and presentations are atypical.