A Large Common Source Outbreak of Salmonella typhimurium Linked to Kuala Terengganu Night Markets, Malaysia, 2014

Abstract

On 1 Mar 2014, the Terengganu District Health Office was notified of ten patients presented with acute gastroenteritis at Sultanah Nur Zahirah Hospital. Their illness was linked to consumption of foods from two night markets. An outbreak investigation was initiated to determine the source of the outbreak. Case finding was conducted in the hospital, and community. Patients were interviewed about demographics, symptoms and food consumption history. Stool samples from patients and food handlers as well as food and environmental samples were collected for laboratory analysis. Suspected food premises were inspected. A case-control study was conducted. Of 169 cases, 68.6% and 32.5% ate food from night markets A and B respectively while 1.2% ate food from both night markets. Major symptom was diarrhea (98.2%). There was one death from hypovolemic shock. Salmonella typhimurium was isolated from 13 patients and one food handler. All isolates showed genetic similarity by pulsed-field gel electrophoresis. The food handler tested to have the infection served the white fried rice sold in both night markets. Cases were 14 (95% CI = 4.05-46.61) and nine (95% CI = 3.36-24.3) times more likely to have consumed white fried rice from night markets A & B respectively. The source of infection was likely to be white fried rice that was prepared at the same place, contaminated by an infected food handler and sold at both night markets.