Waterborne viruses and F-specific coliphages in mixed-use watersheds: Microbial associations, host specificities, and affinities with environmental/land use factors
Jones, T.H., Brassard, J., Topp, E., Wilkes, G., Lapen, D.R. (2017). Waterborne viruses and F-specific coliphages in mixed-use watersheds: Microbial associations, host specificities, and affinities with environmental/land use factors. Applied and Environmental Microbiology, [online] 83(3), http://dx.doi.org/10.1128/AEM.02763-16
Plain language summary
This study is one of the first studies to evaluate in mixed-use, but agriculturally dominated surface waters of Canada, enteric virus prevalence and virus associations with F-coliphage. This study suggested that relationships between viable F-coliphage and molecularly detected viruses do exist, but they are not always positive. Caution should be employed if viable F-coliphage are to be used as indicators of virus presence in surface waters, especially if viruses are detected via molecular methods. This study elucidates the relative role of agriculture, wildlife, and human activity on virus and F-coliphage occurrence. Seasonal and meteorological attributes play a strong role in the occurrences of most virus and F-coliphage targets.
From the years 2008 to 2014, a total of 1,155 water samples were collected (spring to fall) from 24 surface water sampling sites located in a mixed-used but predominantly agricultural (i.e., dairy livestock production) river basin in eastern Ontario, Canada. Water was analyzed for viable F-specific DNA (F-DNA) and F-specific RNA (F-RNA) (genogroup I [GI] to GIV) coliphage and a suite of molecularly detected viruses (norovirus [GI to GIV], torque teno virus [TTV], rotavirus, kobuvirus, adenovirus, astrovirus, hepatitis A, and hepatitis E). F-DNA and F-RNA coliphage were detected in 33 and 28% of the samples at maximum concentrations of 2,000 and 16,300 PFU · 100 ml-1, respectively. Animal TTV, human TTV, kobuvirus, astrovirus, and norovirus GIII were the most prevalent viruses, found in 23, 20, 13, 12, and 11% of samples, respectively. Viable F-DNA coliphage was found to be a modest positive indicator of molecularly detected TTV. F-RNA coliphage, unlike F-DNA coliphage, was a modest positive predictor of norovirus and rotavirus. There were, however, a number of significant negative associations among F-specific coliphage and viruses. F-DNA coliphage densities of > 142 PFU · 100 ml-1 delineated conditions when ~95% of water samples contained some type of virus. Kobuvirus was the virus most strongly related to detection of any other virus. Land use had some associations with virus/F-specific coliphage detection, but season and surface water flow were the variables that were most important for broadly delineating detection. Higher relative levels of detection of human viruses and human F-RNA coliphage were associated with higher relative degrees of upstream human land development in a catchment.