J Korean Med Sci.  2011 Jun;26(6):734-739. 10.3346/jkms.2011.26.6.734.

Norovirus Infections in Asymptomatic Food Handlers in Elementary Schools without Norovirus Outbreaks in Some Regions of Incheon, Korea

• Yu JH
• Kim NY
• Lee EJ
• Jeon IS

• KMID: 1785957
• DOI: http://doi.org/10.3346/jkms.2011.26.6.734

Abstract

Norovirus (NV) has caused large outbreaks of gastroenteritis in schools. Studies of NV epidemiology in schools related to NV outbreaks have been frequently reported. However, reports of that in schools without outbreaks are not found. Presently, NV molecular epidemiology surveillance was carried out in asymptomatic food handlers working at nonoutbreak elementary schools in Incheon, Korea, in March, April and December, 2009. NV prevalence was examined by real-time reverse transcription-PCR (RT-PCR) and the positive products were re-evaluated by conventional RT-PCR for sequencing. Fecal samples (n = 776) were collected from 776 food handlers in 60 schools. NV was detected in 26 of them (3.4%). Of these, 17 (65%) were positive for NV GII and 10 (38%) were positive for NV GI. Of the 26 samples, 19 were positive by conventional RT-PCR. Sequencing of these 19 strains revealed GII/4 (n = 5), GI/6 (n = 3), GI/14 (n = 2), GII/8 (n = 2), GI/2 (n = 2), GI/10 (n = 1), GII/1 (n = 1), GII/3 (n = 1), GII/7 (n = 1), and GII/16 (n = 1). In this survey, the food handler population unrelated to NV outbreaks was found to normally contain asymptomatic carriers of NV. The excretion of NV from asymptomatic food handlers should be an infection source of NV outbreaks.

Keyword

Epidemiology; Norovirus; School

MeSH Terms

Adult
Caliciviridae Infections/*epidemiology/genetics
Feces/virology
Female
Food Handling
Gastroenteritis/*epidemiology/genetics
Genotype
Humans
Male
Middle Aged
Norovirus/genetics/*isolation & purification
Prevalence
RNA, Viral/analysis
Republic of Korea
Reverse Transcriptase Polymerase Chain Reaction
Schools
Sequence Analysis, RNA

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