Foodborne illness outbreaks in gyeonggi province, Korea, following seafood consumption potentially caused by kudoa septempunctata between 2015 and 2016

Objectives: Investigations into foodborne illness, potentially caused by Kudoa septempunctata, has been ongoing in Korea since 2015. However, epidemiological analysis reporting and positive K septempunctata detection in feces in Korea has been limited. The aim of this study was to provide epidemiologic data analysis of possible food poisoning caused by K septempunctata in Korea. Methods: This study reviewed 16 Kudoa outbreak investigation reports, including suspected cases between 2015 and 2016 in Gyeonggi province, Korea. Suspected Kudoa foodborne illness outbreak was defined as "evidence of K septempunctata in at least one sample." The time and place of outbreak, patient symptoms and Kudoa (+) detection rate in feces was analyzed. Results: Kudoa foodborne illness outbreaks occurred in most patients in August (22.6%) and in most outbreaks in April (25%). The attack rate was 53.9% and the average attack rate in patients who had consumed olive flounder was 64.7%. The average incubation period was 4.3 hours per outbreak. Diarrhea was the most common symptom which was reported by 91.5% patients. The Kudoa (+) detection rate in feces was 69.2% of cases. Conclusion: Monthly distribution of Kudoa foodborne illness was different from previous studies. The Kudoa (+) detection rate in feces decreased rapidly between 25.5 and 28.5 hours of the time interval from food intake to epidemiologic survey. To identify effective period of time of investigation, we believe additional study with extended number of cases is necessary.