title: Continuous presence of noroviruses and sapoviruses in raw sewage reflects infections among inhabitants of Toyama, Japan (2006 to 2008).
abstract: Various genotypes of norovirus (NoV) (genogroup I genotype 1 [GI.1], -2, -4, -5, -8, -11, -12, and -14; GII.3, -4, -6, -7, -10, -13, -14, and -15), and sapovirus (SaV) (GI.1 and GI.2, GII.1, and GIV.1) were detected from raw sewage from April 2006 to March 2008, while limited numbers of genotypes of NoV (GI.8, GII.4, GII.6, and GII.13) and SaV (GII.3 and GIV.1) and of NoV (GII.4, GII.7, and GII.13) were detected from clinical cases and healthy children, respectively. During the winter 2006 to 2008, a large number of sporadic gastroenteritis outbreaks and many outbreaks caused by NoV GII.4 occurred among inhabitants in Toyama, Japan. The copy number of genomes of NoV GII detected from raw sewage changed in relation to the number of outbreaks. NoV strains of the same genotypes observed in both raw sewage and human specimens belonged to the same cluster by phylogenetic analysis and had almost identical nucleotide sequences among each genotype. These data suggest that NoVs and SaVs detected from raw sewage reflect the viruses circulating in the community, irrespective of symptoms, and that subclinical infections of NoV are common in Japan. Combined surveys of raw sewage with those of clinical cases help us to understand the relationship between infection of these viruses and gastroenteritis.
authors.affiliation: Department of Virology, Toyama Institute of Health, 17-1 Nakataikoyama, Imizu-shi, Toyama 939-0363, Japan. masae.iwai@pref.toyama.lg.jp
authors.forename: Masae
authors.initials: M
authors.lastname: Iwai
authors.forename: Sumiyo
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Mayumi
authors.initials: M
authors.lastname: Obara
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nakamura
authors.forename: Eiji
authors.initials: E
authors.lastname: Horimoto
authors.forename: Takenori
authors.initials: T
authors.lastname: Takizawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kurata
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Sogen
authors.forename: Kimiyasu
authors.initials: K
authors.lastname: Shiraki
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology*; D016000:Cluster Analysis; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology; D005838:Genotype; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D029341:Sapovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012722:Sewage / Q000821:virology*
chemical_list: D012367:RNA, Viral; D012722:Sewage