The association between the consumption of raw Kudoa septempunctata–infected farmed Paralichthys olivaceus and gastrointestinal symptoms

OBJECTIVES: Kudoa septempunctata has been identified as the causative agent of food poisoning following the consumption of raw farmed Paralichthys olivaceus. However, cohort studies providing robust evidence for an association between K. septempunctata and gastrointestinal symptoms remain limited. This prospective cohort study investigated the association between the consumption of K. septempunctata-infected farmed P. olivaceus and the occurrence of gastrointestinal symptoms. METHODS: Individuals who purchased raw farmed P. olivaceus between 2020 and 2021 were selected as the study population. Study data included 2 rounds of questionnaire surveys administered before and after consumption, 2 muscle specimens obtained from each purchased fish, and human biological specimens collected from individuals who developed gastrointestinal symptoms within 24 hours after consumption. Data were analyzed using the chi-square test and t-test, and the association between consumption of K. septempunctata-infected farmed P. olivaceus and gastrointestinal symptoms was evaluated using relative risk estimates between exposure groups. RESULTS: The relative risk of gastrointestinal symptoms associated with exposure to K. septempunctata-infected P. olivaceus ranged from 71.2 (95% confidence interval [CI], 27.0 to 178.6) to 124.5 (95% CI, 43.5 to 355.0) across the 2 case definitions. A strong and statistically significant association was observed between exposure to K. septempunctata-infected P. olivaceus and the development of acute gastrointestinal symptoms. CONCLUSIONS: These findings indicate both an association and a causal relationship between consumption of K. septempunctata-infected farmed P. olivaceus and the onset of gastrointestinal symptoms.