TY - JOUR
T1 - Weekly variations in norovirus genogroup II genotypes in Japanese oysters
AU - Pu, Jian
AU - Miura, Takayuki
AU - Kazama, Shinobu
AU - Konta, Yoshimitsu
AU - Azraini, Nabila Dhyan
AU - Ito, Erika
AU - Ito, Hiroaki
AU - Omura, Tatsuo
AU - Watanabe, Toru
N1 - Funding Information:
This work was supported by a Core Research for Evolutional Science and Technology (CREST) program, “Innovation of water monitoring system with rapid, highly precise and exhaustive pathogen detection technologies”, of the Japan Science and Technology Agency (JST).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/11/2
Y1 - 2018/11/2
N2 - Increased levels of norovirus contamination in oysters were reportedly associated with a gastroenteritis epidemic occurring upstream of an oyster farming area. In this study, we monitored the norovirus concentration in oysters weekly between November 2014 and March 2015 and investigated the statistical relationship between norovirus genogroup II (GII) concentrations in oyster and sewage samples and the number of gastroenteritis cases in the area using cross-correlation analysis. A peak correlation coefficient (R = 0.76) at a time lag of +1 week was observed between the number of gastroenteritis cases and norovirus GII concentrations in oysters, indicating that oyster contamination is correlated with the number of gastroenteritis cases with a 1-week delay. Moreover, weekly variations in norovirus GII genotypes in oysters were evaluated using pyrosequencing. Only GII.3 was detected in November and December 2014, whereas GII.17 and GII.4 were present from January to March 2015. GII.17 Kawasaki 2014 strains were detected more frequently than GII.4 Sydney 2012 strains in oyster samples, as previously observed in stool and sewage samples collected during the same study period in Miyagi, Japan. Our observations indicate that there is a time lag between the circulation of norovirus genotypes in the human population and the detection of those genotypes in oysters.
AB - Increased levels of norovirus contamination in oysters were reportedly associated with a gastroenteritis epidemic occurring upstream of an oyster farming area. In this study, we monitored the norovirus concentration in oysters weekly between November 2014 and March 2015 and investigated the statistical relationship between norovirus genogroup II (GII) concentrations in oyster and sewage samples and the number of gastroenteritis cases in the area using cross-correlation analysis. A peak correlation coefficient (R = 0.76) at a time lag of +1 week was observed between the number of gastroenteritis cases and norovirus GII concentrations in oysters, indicating that oyster contamination is correlated with the number of gastroenteritis cases with a 1-week delay. Moreover, weekly variations in norovirus GII genotypes in oysters were evaluated using pyrosequencing. Only GII.3 was detected in November and December 2014, whereas GII.17 and GII.4 were present from January to March 2015. GII.17 Kawasaki 2014 strains were detected more frequently than GII.4 Sydney 2012 strains in oyster samples, as previously observed in stool and sewage samples collected during the same study period in Miyagi, Japan. Our observations indicate that there is a time lag between the circulation of norovirus genotypes in the human population and the detection of those genotypes in oysters.
KW - Massive parallel sequencing
KW - Molecular epidemiology
KW - Norovirus
KW - Oyster
KW - Sewage
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U2 - 10.1016/j.ijfoodmicro.2018.06.027
DO - 10.1016/j.ijfoodmicro.2018.06.027
M3 - Article
C2 - 29990639
AN - SCOPUS:85049485416
SN - 0168-1605
VL - 284
SP - 48
EP - 55
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
ER -