title: Temporal dynamics of norovirus determined through monitoring of municipal wastewater by pyrosequencing and virological surveillance of gastroenteritis cases.
abstract: Norovirus is a leading etiological agent of viral gastroenteritis. Because of relatively mild disease symptoms and frequent asymptomatic infections, information on the ecology of this virus is limited. Our objective was to examine the genetic diversity of norovirus circulating in the human population by means of genotyping the virus in municipal wastewater. We investigated norovirus genogroups I and II (GI and GII) in municipal wastewater in Japan by pyrosequencing and quantitative PCR (qPCR) from November 2012 to March 2013. Virological surveillance for gastroenteritis cases was concurrently conducted in the same area. A total of fourteen distinct genotypes in total (GI.1, 3, 4, 6, 7, GII.2, 4, 5, 6, 7, 12, 13, 14, and 17), with up to eight genotypes detected per sample, were observed in wastewater using pyrosequencing; only four genotypes (GI.6, GII.4, 5, and 14) were obtained from clinical samples. Seventy-eight percent of norovirus-positive stool samples contained GII.4, but this genotype was not dominant in wastewater. The norovirus GII.4 Sydney 2012 variant, which appeared and spread during our study period, was detected in both the wastewater and clinical samples. These results suggest that an environmental approach using pyrosequencing yields a more detailed distribution of norovirus genotypes/variants. Thus, wastewater monitoring by pyrosequencing is expected to provide an effective analysis of the distribution of norovirus genotypes causing symptomatic and asymptomatic infections in human populations.
authors.affiliation: New Industry Creation Hatchery Center, Tohoku University, Sendai, Miyagi, 980-8479, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Kazama
authors.affiliation: New Industry Creation Hatchery Center, Tohoku University, Sendai, Miyagi, 980-8479, Japan; Institute for the Advanced Study of Sustainability, United Nations University, Shibuya-ku, Tokyo 150-8925, Japan. Electronic address: masago@unu.edu.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Masago
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tohma
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Souma
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Imagawa
authors.affiliation: Virus Research Center, Clinical Research Division, Sendai Medical Center, Sendai, Miyagi, 983-8520, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Virology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Oshitani
authors.affiliation: New Industry Creation Hatchery Center, Tohoku University, Sendai, Miyagi, 980-8479, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Omura
mesh_terms: D002947:Cities; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D005838:Genotype; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D029322:Norovirus / Q000235:genetics* / Q000302:isolation & purification*; D010802:Phylogeny; D011159:Population Surveillance; D060888:Real-Time Polymerase Chain Reaction; D013997:Time Factors; D062065:Wastewater / Q000821:virology*
chemical_list: D062065:Wastewater
keywords: Norovirus; Pyrosequencing; Virological surveillance; Wastewater