Investigation on food poisoning outbreak in a scout camp, La–ngu District, Satun Province, Thailand, 5–8 April 2017

Abstract

Background: On 5 April 2017, the Surveillance and rapid response team (SRRT) from Satun Provincial Public Health Office was notified of a cluster of suspected food poisoning in the Southern Border Scout camp in La–ngu District, Satun Province. The SRRT teams conducted an investigation to describe epidemiology and risk factors of the outbreak, and to provide prevention and control.
Method: Descriptive epidemiologic study was performed by conducting active case finding in among teachers and students participated in the camp on 5– 6 April 2 0 1 7 . Food poisoning case was defined as anyone who had diarrhea ( loose stool at least 3 times, or at least one time of watery diarrhea/mucous bloody stool) with any of these symptoms: abdominal pain, exhaustion, fever, headache, feeling queasy, and vomiting since 4 April 2017. Environmental study was performed by survey in the camp, and interviewed food handlers about cooking process. Retrospective Cohort Study was conducted among any persons participated in the camp where the outbreak occurred. Logistic regression was performed to determine factors associated food poisoning. Relative risk (RR), Odd ratio (OR), 95% Confidence interval were calculated.
Results: A total of 95 cases, the attack rate (AR) was 28.02% with median age of 16 years. Most patients were students calculated to be 87.37% followed by teachers/children by 12.63%. All patients had diarrhea followed by the symptoms of exhaustion, abdominal pain, headache, feeling queasy, fever, and vomiting. On 4 April 2017, during 1:00–3:00 PM, the first common meal was lunch. And the first patient was ill at approximately 04:00 PM, the incubation period was 3-23 hours, with the mean of 12 hours. The rectal swab from laboratory test revealed that there was non-pathogenic Escherichia coli. Analytic study showed that Spicy Fried Seafood of lunch meal had the relationship with this sickness with RR = 4.29 (95% CI =2.25-8.19).
Conclusion: This outbreak was likely from the common source. According to the incubation period and suspected food, Vibrio parahaemolyticus was the possible cause the outbreak. Recommend to educate the entrepreneur and related persons and to surveillance until 8 April 2017, there was no additional patient.