An outbreak investigation of Salmonella food poisoning in a primary school of Mueang district, Nakhon Sawan province, July 2020

Abstract

The outbreak investigation of Salmonella food poisoning in a primary school, Nakhon Sawan Province, was conducted from July 21-23, 2020. The objectives of the investigation were to confirm a diagnosis of Salmonella food poisoning, determine epidemiological characteristics, identify source and mode of transmission, and recommend for prevention and control measures. Descriptive and unmatched case-control studies served as the methodology for epidemiological study designs. Active case finding was conducted by interviews, an individual in school or a food handler who had developed watery diarrhea, mucous diarrhea, abdominal pain, vomiting, nausea, fever, headache, and fatigue between 18 and 23 July 2020 were categorized as the suspected case and confirmed through laboratory tests to identify causative agents. Results indicated that 192 cases of Salmonella food poisoning were reported, the overall attack rate of 12.09 %. Of these 192 cases, 186 were students and 6 were educational personnel. Most cases presented with watery diarrhea, mucus diarrhea, and abdominal pain after consuming steamed Chinese Chive Dumplings (Gui Chai) in the afternoon of July 20, 2020. Multivariate analysis determined that consumption of Gui Chai was significant, adjusted OR=5.52 (95%CI; 2.26-13.99). Epidemiological findings revealed that Gui Chai was a suspected source of infection and its culture showed a positive result for Salmonella spp. Gui Chai was well steamed over boiling water for five minutes, but there was later contaminating. The outbreak of food poisoning in this primary school at Nakhon Sawan province, was caused by Salmonella spp. contaminated in Gui Chai. The personal hygiene practices of food sellers and the food sanitation adherence among subcontracting chain in food suppliers should be intensified. The surveillance following the outbreak of the disease had been monitored for one week, it revealed no additional cases. Thus, it was regarded as the end of the outbreak.