Food Poisoning Investigation Caused by Norovirus in an Elementary School, Nameuang Sub-district, Meuang District, Ratchaburi, Thailand, 17 – 27 June 2014

Abstract

Food poisoning investigation conducted at a elementary school, Nameuang sub-district, Meuang district, Ratchaburi province during 17 – 27 June 2014. The objectives were to confirmed diagnosis and outbreak, to describe the epidemiological characteristic of the outbreak, to identify the source and etiology of the outbreak and to implement control and prevent future outbreak. Fifty three cases were met case definition of food poisoning in grade 5. Overall attack rate in grade 5 was 13.09%. The highest number of case found in 2 class rooms, class 5/1 and 5/5 total 46 cases (86.79%) and found 1 – 3 cases per class in other classroom. The most common clinical presentations were abdominal pain (88.7%) followed by loose stool (60.4%), nausea (35.8%) and watery diarrhea (22.6%). The epidemic curve of the outbreak demonstrated to be point common source. The estimation of incubation period was 10 hours by the duration of first and last case’s onset. The laboratory results of stool PCR for Norovirus and Rotavirus revealed positive for Norovirus in 5 cases (45.45%) and all negative for Rotavirus and rectal swab culture for enteropathogenic bacteria was also all negative. Among the cases, there is no common food consumed, except pasteurized milk. The contamination of Norovirus might be on the bag of pasteurized milk by the ice in a stored tank. The habit prone to infection was cutting contaminated bag by teeth. There was no new case after follow-up for 4 days.