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VirWaTest, A Point-of-Use Method for the Detection of Viruses in Water Samples

Viruses excreted by humans and animals may contaminate water sources and pose a risk to human health when this water is used for drinking, food ...

University of Barcelona

Universidad de las Américas

Disinfection by low-pressure monochromatic ultraviolet (UVC) radiation (253.7 nm) became an important technique to sanitize drinking water and also wastewater in tertiary treatments. In order to prevent the transmission of waterborne viral diseases, the analysis of the disinfection kinetics and the quantification of infectious viral pathogens and indicators are highly relevant and need to be addressed. The families Adenoviridae and Polyomaviridae comprise human and animal pathogenic viruses that have been also proposed as indicators of fecal contamination in water and as Microbial Source Tracking tools. While it has been previously suggested that dsDNA viruses may be highly resistant to UVC radiation compared to other viruses or bacteria, no information is available on the stability of polyomavirus toward UV irradiation. Here, the inactivation of dsDNA (HAdV2 and JCPyV) and ssRNA (MS2 bacteriophage) viruses was analyzed at increasing UVC fluences. A minor decay of 2-logs was achieved for both infectious JC polyomaviruses (JCPyV) and human adenoviruses 2 (HAdV2) exposed to a UVC fluence of 1,400 J/m(2), while a decay of 4-log was observed for MS2 bacteriophages (ssRNA). The present study reveals the high UVC resistance of dsDNA viruses, and the UV fluences needed to efficiently inactivate JCPyV and HAdV2 are predicted. Furthermore, we show that in conjunction with appropriate mathematical models, qPCR data may be used to accurately estimate virus infectivity.

UVC Inactivation of dsDNA and ssRNA Viruses in Water: UV Fluences and a qPCR-Based Approach to Evaluate Decay on Viral Infectivity.

Hepatitis E Virus (HEV) is a major cause of waterborne outbreaks in areas with poor sanitation. As safe water supplies are the keystone for preventing HEV outbreaks, data on the efficacy of disinfection treatments are urgently needed. Here, we evaluated the ability of UV radiation and flocculation-chlorination sachets (FCSs) to reduce HEV in water matrices. The HEV-p6-kernow strain was replicated in the HepG2/C3A cell line, and we quantified genome number using qRT-PCR and infectivity using an immunofluorescence assay (IFA). UV irradiation tests using low-pressure radiation showed inactivation kinetics for HEV of 99.99% with a UV fluence of 232J/m(2) (IC 95%, 195,02-269,18). Moreover, the FCSs preparations significantly reduced viral concentrations in both water matrices, although the inactivation results were under the baseline of reduction (4.5 LRV) proposed by WHO guidelines.

UV disinfection and flocculation-chlorination sachets to reduce hepatitis E virus in drinking water.

In Quito, the microbiological contamination of surface water represents a public health problem, mainly due to the lack of sewage treatment from urban wastewater. Contaminated water contributes to the transmission of many enteric pathogens through direct consumption, agricultural and recreational use. Among the different pathogens present in urban discharges, viruses play an important role on disease, being causes of gastroenteritis, hepatitis, meningitis, respiratory infections, among others. This study analyzes the presence of viruses in highly impacted surface waters of urban rivers using next-generation sequencing techniques. Three representative locations of urban rivers, receiving the main discharges from Quito sewerage system, were selected. Water samples of 500 mL were concentrated by skimmed-milk flocculation method and the viral nucleic acid was extracted and processed for high throughput sequencing using Illumina MiSeq. The results yielded very relevant data of circulating viruses in the capital of Ecuador. A total of 29 viral families were obtained, of which 26 species were associated with infections in humans. Among the 26 species identified, several were related to gastroenteritis: Human Mastadenovirus F, Bufavirus, Sapporovirus, Norwalk virus and Mamastrovirus 1. Also detected were: Gammapapillomavirus associated with skin infections, Polyomavirus 1 related to cases of kidney damage, Parechovirus A described as cause of neonatal sepsis with neurological affectations and Hepatovirus A, the etiologic agent of Hepatitis A. Other emergent viruses identified, of which its pathogenicity remains to be fully clarified, were: Bocavirus, Circovirus, Aichi Virus and Cosavirus. The wide diversity of species detected through metagenomics gives us key information about the public health risks present in the urban rivers of Quito. In addition, this study describes for the first time the presence of important infectious agents not previously reported in Ecuador and with very little reports in Latin America.

Laura Guerrero-Latorre

University of Barcelona

VirWaTest, A Point-of-Use Method for the Detection of Viruses in Water Samples