A Cluster of Haff Disease Associated with Consumption of Cyprinus carpio rubrofuscus - Heyuan City, Guangdong Province, China, 2026.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Haff disease is a foodborne rhabdomyolysis syndrome. In China, most reported cases are associated with crayfish, whereas freshwater fish-associated cases are rare, with only two previously documented clusters.

WHAT IS ADDED BY THIS REPORT?: This cluster confirmed Cyprinus carpio rubrofuscus (red-tailed carp) as a Haff disease vector, representing the second carp-associated cluster in China and the first from the Dongjiang River Basin. All five consumers of cooked carp developed rhabdomyolysis (attack rate: 100%, 5/5; Fisher's exact test, P=0.0079), whereas the two non-consumers remained healthy, indicating that the unidentified causative factor was heat-stable.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Clinicians evaluating patients with unexplained rhabdomyolysis should routinely ask about recent consumption of aquatic products. Local health authorities should include wild-caught freshwater fish in risk communication.