title: Detection, quantitation, and phylogenetic analysis of noroviruses in Japanese oysters.
abstract: Noroviruses (NVs) cause many cases of oyster- or clam-associated gastroenteritis in various countries. We collected 191 samples from Japanese oysters intended for raw consumption that had been harvested from the sea in two different areas between December 2001 and February 2002. To detect, quantitate, and phylogenetically analyze the NV genome in purified concentrates from the stomachs and digestive diverticula of these oysters, we amplified the NV capsid gene by reverse transcription-PCR. Phylogenetic analysis was performed by using the neighbor-joining method. We detected the NV genome in 17 of 191 oysters (9%). Phylogenetic analysis indicated genogroup I (Norwalk virus type) in 3 of the 17 oysters and genogroup II (Snow Mountain virus type) in the other 14. Both genogroups showed wide genetic diversity. To quantify the NV capsid gene in these oysters, we performed real-time PCR using genogroup-specific probes. More than 10(2) copies of the NV genome were detected in 11 of 17 oysters. The results suggested that about 10% of Japanese oysters intended for raw consumption harbored NVs, and more than 50% of those oysters in which NVs were detected had a large amount.
authors.affiliation: Yamaguchi Prefectural Research Institute of Public Health, Yamaguchi, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nishida
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kimura
authors.forename: Mika
authors.initials: M
authors.lastname: Saitoh
authors.forename: Michiyo
authors.initials: M
authors.lastname: Shinohara
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kato
authors.forename: Shinji
authors.initials: S
authors.lastname: Fukuda
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Munemura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mikami
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kawamoto
authors.forename: Miho
authors.initials: M
authors.lastname: Akiyama
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Kanako
authors.initials: K
authors.lastname: Nishi
authors.forename: Kunihisa
authors.initials: K
authors.lastname: Kozawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishio
mesh_terms: D000818:Animals; D002213:Capsid; D036022:Capsid Proteins / Q000235:genetics; D007564:Japan; D029322:Norovirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D010125:Ostreidae / Q000821:virology*; D010802:Phylogeny; D012367:RNA, Viral / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012758:Shellfish / Q000821:virology*
chemical_list: D036022:Capsid Proteins; D012367:RNA, Viral