Food poisoning outbreak in tour group at a hotel, Koh Chang District, Trat Province, 11-13 June 2016

Abstract

Background: On 12^th June 2016 at 10.00 AM, Epidemiology section of Trat Provincial Health Office was informed by the International Clinic Koh Chang There were 11 patients with abdominal pain, nausea and vomiting. All patients were tour group member and some hotel employee. The surveillance and rapid response team (SRRT) from Trat province and Koh Chang district conducted the investigation during 12-13 June 2016 in order to confirm the diagnosis, describe outbreak characteristics, find the cause and the prevent and control measures.
Method: Descriptive epidemiological study and case-control study were set by case definition as the tour group member of company A and the hotel staff who joined in the hotel party at the evening on 11 June 2016 and had at least one of these symptoms; abdominal pain, watery diarrhea, nausea or vomiting. Data were collected by interviewing and recording in the investigation form. Collecting specimen for laboratory testing and environmental survey were done too. Odds ratio and 95% Confidence interval were calculated by Epi Info program 3.5.
Results: The results showed 119 cases of food poisoning and 46.12 percentage of attack rate. The patients consisted of 113 tour group members and 6 people of the hotel staff. The outbreak pattern was point common source. Most patients (87.37 %) had abdominal pain; followed by diarrhea, vomiting, nausea, watery diarrhea and fatigue respectively. The laboratory result found Vibrio parahaemolyticus. There were three kinds of seafood with having statistical significance; baked mussels with OR 6.26 (95% CI, 3.60 - 10.87), steamed shrimp with OR 7.45 (95% CI, 3.95 - 14.07), grilled squid with OR 2.92 (95% CI, 1.72 - 4.97).
Conclusions: The cause of outbreak might be the baked mussels, steamed shrimp, and grilled squid. All suspected foods, not the hotel foods, were ordered by the tour company. The outbreak causation might be occured by contaminating during rawfood transportation, or washing the raw food before cooking, or not cooking well, or keeping the cooked food too long before eating. Then be careful when bringing food from outside hotel to join the party. All the party foods should be cooked well and serve immediately.