Food Poisoning Outbreak in School A, Banbeung District, Chonburi Province, September 2010

Abstract

Background: A Cluster of abdominal pain, diarrhea, vomiting and weakness of students from school A in Chonburi Province was reported on September 8, 2010. An investigation was performed to verify an etiology of the outbreak, identify source and risk factors, and recommend control measures.
Methods: History of illness and food consumption was collected by questionnaire interviews. Treatment data from hospital were reviewed. Following active case finding, a case-control study was conducted for identification of risk factors and presented by Odds Ratio (OR) and 95%CI. Rectal swabs and swab specimens from hands of food handlers, glasses, dishes, cooking utensils and water samples were collected for bacterial cultures.
Results: Eighteen cases of students were included in the analysis. The epidemic curve was compatible to a common source outbreak. The mean incubation period was 4 hour and 16 minutes, ranged from 30 minutes to 11 hours and 30 minutes. By comparing 18 cases to 40 students of control group, the risk foods were pineapple curry with pork and sour soup with mussel and shrimp with OR = 11.67 (95%CI = 2.47, 62.89) and 13.91 (95%CI = 1.64, 307.30), respectively. Laboratory reports were negative for pathogenic bacteria.
Conclusions: Based on outbreak investigation findings, the most suspected etiology was toxin from Staphylococcus aureus that might be contaminated in the suspected food. After investigation of cooking processes and literature review, the most suspected food ingredient was boiled mussel bought from a market and inappropriately processed before cooking. Prevention and control measures including health education, sanitation control, annual health check-up, self care hygiene and local network surveillance have been implemented.