Food poisoning Outbreak in a school Kaeng Si Phum Subdistrict, Phu Luang District, Loei Province, 23 – 24 May 2022: Matched case-control study

Abstract

Food poisoning outbreak investigation report in a school Kaeng Si Phum Subdistrict, Phu Luang District, Loei Province, for the purpose of confirming diagnosis and outbreak study the epidemiological characteristics of the disease by person, time and place to find the cause. Find the source of the disease, find risk factors and to find appropriate preventive and control measures. Methods include data collection of patients receiving treatment in Phu Luang Hospital and finding more patients in schools. Finding food that is a risk factor, environmental survey, cooking process and collecting samples for laboratory testing to detect toxins and pathogens. The result of investigations found that, 84 cases were found with an attack rate of 29.3%, of which 59 were hospitalized (70.2%), and 25 were found in the community (29.8%). Twelve cases were admitted in hospital (14.3 percent of all patients) and no fatalities. The majority of patients were 81 students (96.4%), followed by 2 teachers (2.4%). The median age was 11 years (minimum 2 years, maximum 45 years). Most patients had nausea/vomiting (85.7%), abdominal pain (69.0%), watery bowel movements (51.2%), and 3 or more liquid bowel movements (32.1%). This common source outbreak had the shortest incubation period of 4 hours, with an average incubation period of 5.34 hours (SD. ±1.36). The first case was found on May 23, 2022 at 4 p.m. The most cases were found on May 23, 2022 from 5:00 p.m. – 5:59 p.m. The highest morbidity rate was found in primary school grade 3 (82.6%), grade 6 (47.6%) and grade 5 (44.0%), the lowest morbidity rate was found in first grade students (5.9 percent). The morbidity rate among teachers and personnel was 11.1 percent. From a retrospective analytical epidemiological study (Matched case-control) by controlling for variables and other risk factors with multiple logistic regression, it was found that boiled chicken (from the chicken rice menu) was significantly associated with food poisoning patients with an adjusted odds ratio of 87.05 (95% CI; 11.58 – 654.64). The results of laboratory tests revealed no human pathogens, food and water samples, knives and cutting boards samples. The study of the environment and the cooking process of chicken rice found that it was joint cooking between the cook and the assistant (husband) by sitting on the floor in their own home. Procedures that may be contaminated with germs Staphylococcus aureus was tearing of a boiled chicken by an assistant and bringing torn boiled chicken to put on a container. The results of this investigation demonstrate the importance of hygienic cooking preparation at every step.