Food poisoning outbreak in travelers at a resort, Klang Subdistrict, Meuang District, Rayong Province, Thailand, 7–9 July 2016

Abstract

Background: On 8 July 2016, a cluster of food poisoning among a travelers was notified by the emergency room at Rayong Hospital. All travelers stayed in a same resort at Klang subdistrict. We started outbreak investigation with aimed to identify etiologic agent, source and risk factor, to describe the burden of disease including to recommend the specific control measures.
Methods: Descriptive study was conducted by interviewing cases and food handlers in the restaurant. We reviewed medical records. Active case finding was done among the travelers by standard questionnaire. Retrospective cohort study was carried out for risk factor identification. Laboratory investigation was done in stool and vomitus samples and sent for enteropathogenic bacteria isolation. Food sanitation in the seafood shops were inspected and rectal swabs among food handlers and environmental survey was done.
Results: There were 13 cases met case definition and attack rate was 54.16%. The most clinical presentation was watery diarrhea (60%), followed by abdominal pain (48%), nausea (41%), and weakness (40%). Three cases were severe with fever, cramp and hypotension. Epidemic curve showed point common source pattern. The incubation period was approximately 9 - 14 hours. Analytic study result suggested consumption of streamed green mussel as a suspected risk factor (p = 0.06). Rectal swab culture yielded positive for Aeromonas spp., Vibrio parahemolyticus, Salmonella spp., Vibrio fluvialis, Staphylococus aureus. Aeromonas spp. was the most positive yield organism (8/13). There were 2 carriers in food handlers and 4 food items were contaminated.
Conclusions: The most likely causative agent food poisoning outbreak was Aeromonas spp due to compatible with clinical presentation and incubation period. However, there was possible mixed infections due to poor food sanitation. The food sanitation needed to be improved. Frequent hand washing, disinfecting contaminated surfaces and high temperature steamed mussel were recommended to minimize the risk.