Outbreak of Food Poisoning Caused by Salmonella enteritidis and Secondary Transmission in Hokkaido in 2011

Abstract

  A school lunch contaminated with Salmonella enteritidis (O-9) in broccoli salad was served to 2640 children and teachers in elementary and junior high schools on February 9. The first group of 1600 patients presented with high fever, abdominal pain, vomiting, diarrhea, and bloody diarrhea. A total of 30 people were admitted to hospital, and the incubation period was about 3 days. The second group of 70 patients included 6 admitted to hospital, and the incubation period was about 25 days. Almost all secondary patients were intrafamilial transmissions from the primary patients. Evaluation of Pulsed-Field Gel Electrophoresis patterns suggested that the Salmonella strain isolated from the secodary patients was the same as that from the broccoli salad and the primary patients. The third group of patients presented from days 27-40. Salmonella was detected from a long time carrier with no symptoms and unknown origin in little children under school age. The number of patients decreased after environmental interventions in the school lavatory. Early intervention and long-time observations are needed during Salmonella outbreaks.