First Local Cluster of Clonorchiasis Caused by Consumption of Raw Freshwater Fish - Zhengzhou City, Henan Province, China, 2026.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Clonorchiasis, a major foodborne parasitic disease in China, is transmitted by eating raw or undercooked freshwater fish and shrimp containing metacercariae. Although prevalent in southeastern and northeastern China, it remains low-endemic in Henan, where raw freshwater fish is not traditionally eaten; indigenous cases are rare and most infections are imported.

WHAT IS ADDED BY THIS REPORT?: This report is China's first local clonorchiasis cluster in a low-endemic region. The Zhengzhou outbreak was linked to raw freshwater fish eaten at a dinner and drew online public concern. Three symptomatic and two asymptomatic patients were confirmed by the provincial CDC, and all recovered after anthelmintic treatment.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Rising popularity of raw freshwater fish has raised clonorchiasis risk in low-endemic regions. Authorities should strengthen public health education, train medical staff, and improve collaboration with market supervision agencies. Standardized surveillance of aquatic products, regular release of results, and coordinated responses to clusters and online public concern are essential.