Use of viral pathogens and indicators to differentiate between human and non-human fecal contamination in a microbial source tracking comparison study

Abstract

Assays for the detection and typing of adenoviruses, enteroviruses and F+ specific coliphages were performed on samples created as part of a national microbial source tracking methods comparison study. The samples were created blind to the researchers, and were inoculated with a variety of types of fecal contamination source (human, sewage, dog, seagull and cow) and mixtures of sources. Viral tracer and pathogen assays demonstrated a general ability to discriminate human from non-human fecal contamination. For example, samples inoculated with sewage were correctly identified as containing human fecal contamination because they contained human adenovirus or human enterovirus. In samples containing fecal material from individual humans, human pathogen analysis yielded negative results probably because the stool samples were taken from healthy individuals. False positive rates for the virus-based methods (0-8%) were among the lowest observed during the methods comparison study. It is suggested that virus-based source tracking methods are useful for identification of sewage contamination, and that these methods may also be useful as an indication of the public health risk associated with viral pathogens. Overall, virus-based source tracking methods are an important approach to include in the microbial source tracking 'toolbox'.

Enteric Viruses of Humans and Animals in Aquatic Environments: Health Risks, Detection, and Potential Water Quality Assessment Tools

“…PCR viral detection is less laborious and time-consuming and also more specific and sensitive than cell culture (Table 2) (27,66,79). Results from PCR assays can be obtained within 24 h of sampling, compared to days or weeks of incubation for cell culture assay (62,120). PCR is also capable of differentiating specific viruses (79,86,127).…”

“…However, the cost of a real-time PCR instrument is still substantially more than that of a conventional PCR instrument, and in some cases, real-time PCR has been shown to be less sensitive than conventional RT-PCR and nested PCR (120). Noble et al (120) reported that human adenovirus 40 was detected by real-time PCR in only two of the four samples positive for adenoviruses by conventional nested PCR; none of the samples that were positive for enteroviruses by conventional RT-PCR was detected by real-time RT-PCR.…”

“…Furthermore, they may regrow in the environment after being excreted from their host (148). The ability to identify the dominant sources of fecal pollutants in aquatic environments has become increasingly important in water quality management and remediation; however, tracking the host source of bacterial indicators in environmental waters is impossible without laborious and extensive assays such as multiple antibiotic resistance profiling and ribotyping (39,120). Complicating matters, studies have shown that in coastal and marine waters traditional bacterial indicators generally die off quickly compared to viruses and protozoa (15,147).…”

First description of Adenovirus, Enterovirus, Rotavirus and Torque teno virus in water samples collected from the Arroio Dilúvio, Porto Alegre, Brazil

“…Additionally, non-enveloped viruses are more resistant to decontamination processes used in both drinking and wastewater treatments as well as being more species-specifical than bacteria, which may indicate them as candidates for microbial source tracking (Noble et al, 2003;. Therefore, the analysis of viruses in conjunction with bacteria may be advantageous for detection and identification of sources for fecal contamination.…”

Field-based evaluation of a male-specific (F+) RNA coliphage concentration method

“…ing applications (Jofre et al, 2011;Noble et al, 2003;Scott et al, 2002). GI and GIV have been found predominantly associated with animal feces and GII and GIII in human sources of fecal contamination (Osawa et al, 1981;Schaper et al, 2002).…”