title: Surveillance of enteric viruses and coliphages in a tropical urban catchment.
abstract: An assessment of the occurrence and concentration of enteric viruses and coliphages was carried out in highly urbanized catchment waters in the tropical city-state of Singapore. Target enteric viruses in this study were noroviruses, adenoviruses, astroviruses and rotaviruses. In total, 65 water samples were collected from canals and the reservoir of the Marina catchment on a monthly basis over a period of a year. Quantitative PCR (qPCR) and single agar layer plaque assay (SAL) were used to enumerate target enteric viruses and coliphages in water samples, respectively. The most prevalent pathogen were noroviruses, detected in 37 samples (57%), particularly norovirus genogroup II (48%), with a mean concentration of 3.7 × 10(2) gene copies per liter. Rotavirus was the second most prevalent virus (40%) with a mean concentration of 2.5 × 10(2) GC/L. The mean concentrations of somatic and male-specific coliphages were 2.2 × 10(2) and 1.1 × 10(2) PFU/100 ml, respectively. The occurrence and concentration of each target virus and the ratio of somatic to male-specific coliphages varied at different sampling sites in the catchment. For sampling sites with higher frequency of occurrence and concentration of viruses, the ratio of somatic to male-specific coliphages was generally much lower than other sampling sites with lower incidences of enteric viruses. Overall, higher statistical correlation was observed between target enteric viruses than between enteric viruses and coliphages. However, male-specific coliphages were positively correlated with norovirus concentrations. A multi-level integrated surveillance system, which comprises the monitoring of bacterial indicators, coliphages and selected enteric viruses, could help to meet recreational and surface water quality criteria in a complex urbanized catchment.
authors.affiliation: Department of Civil and Environmental Engineering, Faculty of Engineering, National University of Singapore, Blk E1A-07-03, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Rezaeinejad
authors.affiliation: Department of Civil and Environmental Engineering, Faculty of Engineering, National University of Singapore, Blk E1A-07-03, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: G G R V
authors.initials: GG
authors.lastname: Vergara
authors.affiliation: Technology and Water Quality Office, Public Utilities Board, Singapore.
authors.forename: C H
authors.initials: CH
authors.lastname: Woo
authors.affiliation: Technology and Water Quality Office, Public Utilities Board, Singapore.
authors.forename: T T
authors.initials: TT
authors.lastname: Lim
authors.affiliation: Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Sobsey
authors.affiliation: Department of Civil and Environmental Engineering, Faculty of Engineering, National University of Singapore, Blk E1A-07-03, 1 Engineering Drive 2, Singapore 117576, Singapore. Electronic address: ceeginyh@nus.edu.sg.
authors.forename: K Y H
authors.initials: KY
authors.lastname: Gin
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000302:isolation & purification; D003090:Coliphages / Q000235:genetics / Q000302:isolation & purification*; D004770:Enterovirus / Q000235:genetics / Q000302:isolation & purification*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000821:virology*; D029322:Norovirus / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011998:Recreation; D012401:Rotavirus / Q000235:genetics / Q000302:isolation & purification; D012621:Seasons; D012846:Singapore; D014329:Tropical Climate; D014506:Urban Renewal; D014871:Water Microbiology; D060753:Water Quality
keywords: Coliphages; Enteric viruses; Quantitative PCR; Recreational water quality; Urban catchment