Molecular detection and genotyping of human noroviruses in influent and effluent water at a wastewater treatment plant in Japan.
OBJECTIVE
To investigate the prevalence, seasonality and genotype distribution of human noroviruses (NoVs) in wastewater in Japan.


RESULTS
Influent and effluent water samples were collected monthly for a year from a wastewater treatment plant and examined for the presence of genogroups I and II (GI and GII) NoVs. Using real-time reverse transcription (RT)-PCR assays, 12 (100%) influent and six (50%) effluent samples were positive for both GI and GII NoV genomes, with a higher prevalence in winter. A total of 152 different NoV strains, comprising 84 GI and 68 GII strains, were identified using seminested RT-PCR assays followed by cloning and sequence analysis. These strains were classified into nine GI genotypes (GI/1, 2, 4, 5, 8, 9, 11, 12 and 14) and 13 GII genotypes (GII/1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15 and 16), showing considerable genetic diversity.


CONCLUSIONS
Based on the partial capsid gene sequences, we identified a great number of NoV strains belonging to many genotypes, demonstrating that genetically diverse NoV strains are co-circulating in aquatic environments and human populations.


CONCLUSIONS
Our results clearly demonstrate the seasonal trend and genetic diversity of NoVs in wastewater.
Department of Soil, Water and Environmental Science, The University of Arizona, Tucson, AZ 85721, USA. kitajima.masaaki@gmail.com
M
M
Kitajima
E
E
Haramoto
C
C
Phanuwan
H
H
Katayama
H
H
Furumai
D036022:Capsid Proteins / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D007564:Japan; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D017422:Sequence Analysis, DNA; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000032:analysis; D018508:Water Purification / Q000379:methods*
D036022:Capsid Proteins; D004279:DNA, Viral; D014867:Water