Plant Poisoning Outbreak in a Primary School in the northern Thailand, October 2015

Abstract

On 6 Oct 2015, the Thailand Bureau of Epidemiology was notified of a food poisoning outbreak among students in a primary school. An investigation was performed to verify the diagnosis and outbreak, describe epidemiological characteristics, identify the source, and provide proper recommendations in order to prevent further outbreaks. Descriptive and retrospective cohort studies were conducted. Medical records at the hospital were reviewed, and teachers, students, cooks and janitors from the school were interviewed. A suspected case was a person in the school with at least two of the followings: nausea, vomiting, abdominal pain or diarrhea during 5-9 Oct 2015. The water samples were sent to the National Institute of Health for bacterial culture. The suspected plant was examined at the Plant Varieties Protection Division for species identification. Bivariate analysis was used to determine the food items associated with illness. The attack rate was 28.8% with 19 suspected cases out of total 66. Most common symptoms included nausea (85.0%), vomiting (85.0%) and abdominal pain (60.0%). All of the suspected cases consumed the coral plant (Jatropha multifida), which was also the only significant risk for the illness (P value <0.001). Therefore, this event was a coral plant poisoning outbreak. To prevent future outbreaks, a fence around the herb garden with a warning sign should be set up in the school, along with adequate warning of herb toxicity.