An Outbreak of Gastroenteritis due to Salmonella in a Secondary School, Phuket, Thailand

Abstract

Food borne disease outbreaks were commonly reported in developing countries. Children are more effected with higher incidence and virulence than other groups. On December 7, 2011, there were 14 gastroenteritis patients which were students and teachers from a secondary school. The retrospective cohort study was immediately conducted in order to identify the cause and to control this outbreak. Active case finding was done. Data was collected by direct interview methods. There were a total of 218 cases; an attack rate was 10.34 percent. Abdominal pain and watery diarrhea were prominent symptoms. The highest attack rate was found in grade 7, grade 10 students and teachers which were assigned to have lunch at cafeteria A. Rice mixed with shrimp paste, a lunch dish served at the cafeteria A on December 6 showed statistical significant association (risk ratio 16.16). Salmonella group D was identified in 12 samples of patients’ stool, 2 samples of food handler s’ stool, and 5 food and environment samples. Many clues suggest that rice mixed with shrimp paste was the source of this outbreak, even without supporting evidence of bacterial culture. General and specific control measures were in place accordingly.