Surveillance To Prevent the Spread of Norovirus Outbreak from Asymptomatic Food Handlers during the PyeongChang 2018 Olympics

Abstract

Human noroviruses are major causes of nonbacterial gastroenteritis and are transmitted by both food and water, as well as person-to-person. Asymptomatic norovirus infection of food handlers may play a role in transmission. The outbreak of norovirus infections was recognized in the PyeongChang Winter Olympics, starting with security staff on 3 February 2018. The Ministry of Food and Drug Safety in the Republic of Korea conducted norovirus surveillance from asymptomatic food handlers of food-catering facilities related to the Olympics to prevent the spread of noroviruses. Rectal swab samples (707) from food handlers were collected and examined for noroviruses by using real-time reverse transcription PCR and conventional reverse transcription PCR. Five of 707 samples were identified as noroviruses. Genotypes of the norovirus-positive samples were determined with sequencing analysis. Identified genotypes of norovirus in asymptomatic food handlers included GI.3, GII.4, and GII.17. The GII.17 strain was prevalent among the genotypes, accounting for three of five detections. Food handlers with noroviruses detected in rectal swabs were excluded from cooking, and all food handled by infected food handlers was discarded. Surveillance of norovirus infection for food handlers contributed to preventing norovirus spread.