A review on recent progress in the detection methods and prevalence of human enteric viruses in water

Abstract

Waterborne human enteric viruses, such as noroviruses and adenoviruses, are excreted in the feces of infected individuals and transmitted via the fecal-oral route including contaminated food and water. Since viruses are normally present at low concentrations in aquatic environments, they should be concentrated into smaller volumes prior to downstream molecular biological applications, such as quantitative polymerase chain reaction (qPCR). This review describes recent progress made in the development of concentration and detection methods of human enteric viruses in water, and discusses their applications for providing a better understanding of the prevalence of the viruses in various types of water worldwide. Maximum concentrations of human enteric viruses in water that have been reported in previous studies are summarized to assess viral abundances in aquatic environments. Some descriptions are also available on recent applications of sequencing analyses used to determine the genetic diversity of viral genomes in water samples, including those of novel viruses. Furthermore, the importance and significance of utilizing appropriate process controls during viral analyses are discussed, and three types of process controls are considered: whole process controls, molecular process controls, and (reverse transcription (RT)-)qPCR controls. Although no standards have been established for acceptable values of virus recovery and/or extraction-(RT-)qPCR efficiency, use of at least one of these appropriate control types is highly recommended for more accurate interpretation of observed data.

Norovirus and human adenovirus occurrence and diversity in recreational water in a karst aquifer in the Yucatan Peninsula, Mexico

“…The karst aquifer system of the YP is one of the largest in the world where groundwater flows varies by direction and scale (Bauer‐Gottwein et al ), and enables the transport and dilution of contaminants over time (Mahler et al ; Bauer‐Gottwein et al ). Here, the results of qPCR amplification detected viral concentrations ranging within values reported previously in groundwater for NoV GI (10 2 GC l −1 ) and HAdV (10 1 –10 2 GC l −1 ) (Haramoto et al ). Furthermore, the highest concentrations of NoV GI, NoV GII and HAdV were detected in freshwater sinkholes in urban areas, and in sites used for recreational activities, respectively, providing compelling evidence of health risks to local inhabitants and visitors by accidental water ingestion at these urban and recreational sites.…”

“…Viruses are well‐documented contaminants of aquatic environments, and the prevalence of one enteric virus type over another can vary depending on water type, season and environmental factors such as water, temperature and light intensity (Wyn‐Jones et al ; Haramoto et al ). To date, there have been relatively few studies that have determined and quantified enteric viruses in karst aquifers (Johnson et al ).…”

“…In addition, differences from season to season can influence virus prevalence in aquatic environments. For example, NoVs often occur at high concentrations during the winter, while in contrast, HAdVs are detectable year‐round (Haramoto et al ), and sometimes, at higher concentrations in the dry season (Tao et al ). In this study, the most prevalent genotype was NoV GII in freshwater, which is consistent with results from previous studies (Wyn‐Jones et al ; Hata et al ).…”

“…Even though, detection of multiple genotypes in water environments is common (Kitajima et al ; Kim et al ), in this study five NoVs genotypes were identified from which only NoV GII 17 was previously reported to occur in the Mexican population (García et al ). This low relative diversity of NoV genotypes could possibly be explained by a less than optimal number of clones selected for DNA sequencing, however, historically at least eight clones per sample has been recommended based on other environmental studies (Haramoto et al ). In water environments the GI.2 genotype has been reported from tropical urban surface (Aw et al ), and recreational waters (Wyn‐Jones et al ) worldwide; whereas the GII.4 NoV genotype is among the genotypes most often associated with human clinical samples (Kazama et al ).…”

Differences in Viral Disinfection Mechanisms as Revealed by Quantitative Transfection of Echovirus 11 Genomes

“…impacts on human health (1). Although traditional wastewater and drinking water treatment schemes greatly reduce the prevalence of these viruses, some viruses have been found to withstand treatment and therefore circulate in otherwise healthy populations on a regular basis (2,3). Compared to other pathogens, viruses are more difficult to remove by physical water treatment methods (e.g., sedimentation or filtration) due to their small size; therefore, the inclusion of a disinfection step is of key importance to ensure public health (4).…”