Kauppinen A, Pitkänen T, Miettinen IT. Persistent Norovirus Contamination of Groundwater Supplies in Two Waterborne Outbreaks. Food and environmental virology. 2017 Oct 11. doi: 10.1007/s12560-017-9320-6.
Microbiological contamination of groundwater supplies causes waterborne outbreaks worldwide. In this study, two waterborne outbreaks related to microbiological contamination of groundwater supplies are described. Analyses of pathogenic human enteric viruses (noroviruses and adenoviruses), fecal bacteria (Campylobacter spp. and Salmonella spp.), and indicator microbes (E. coli, coliform bacteria, intestinal enterococci, Clostridium perfringens, heterotrophic plate count, somatic and F-specific coliphages) were conducted in order to reveal the cause of the outbreaks and to examine the effectiveness of the implemented management measures. Moreover, the long-term persistence of noro- and adenovirus genomes was investigated. Noroviruses were detected in water samples from both outbreaks after the intrusion of wastewater into the drinking water sources. In the outbreak I, the removal efficiency of norovirus genome (3.0 log10 removal) in the sand filter of onsite wastewater treatment system (OWTS) and during the transport through the soil into the groundwater well was lower than the removal efficiencies of E. coli, coliform bacteria, intestinal enterococci, and spores of C. perfringens (6.2, 6.0, > 5.9, and > 4.8 log10 removals, respectively). In the outbreak II, cleaning of massively contaminated groundwater well and drinking water distribution network proved challenging, and noro- and adenovirus genomes were detected up to 3 months (108 days). The long-term persistence study showed that noro- and adenovirus genomes can remain detectable in the contaminated water samples up to 1277 and 1343 days, respectively. This study highlights the transport and survival properties of enteric viruses in the environment explaining their potency to cause waterborne outbreaks.
Kunze A, Pei L, Elsässer D, Niessner R, Seidel M. High performance concentration method for viruses in drinking water. Journal of Virological Methods. 2015 Jun 18. pii: S0166-0934(15)00223-2. doi: 10.1016/j.jviromet.2015.06.007.
According to the risk assessment of the WHO, highly infectious pathogenic viruses like rotaviruses should not be present in large-volume drinking water samples of up to 90m3. On the other hand, quantification methods for viruses are only operable in small volumes, and presently no concentration procedure for processing such large volumes has been reported. Therefore, the aim of this study was to demonstrate a procedure for processing viruses in-line of a drinking water pipeline by ultrafiltration (UF) and consecutive further concentration by monolithic filtration (MF) and centrifugal ultrafiltration (CeUF) of viruses to a final 1-mL sample. For testing this concept, the model virus bacteriophage MS2 was spiked continuously in UF instrumentation. Tap water was processed in volumes between 32.4m3 (22h) and 97.7m3 (72h) continuously either in dead-end (DE) or cross-flow (CF) mode. Best results were found by DE-UF over 22h. The concentration of MS2 was increased from 4.2×104GU/mL (genomic units per milliliter) to 3.2×1010GU/mL and from 71PFU/mL to 2×108PFU/mL as determined by qRT-PCR and plaque assay, respectively.
Posted in Viruses
Hsu B-M, Chen C-H, Wan M-T, Chang P-J, Po-Jen, Fan C. Detection and identification of enteroviruses from various drinking water sources in Taiwan. Journal of Hydrology 2009 365(1):134-139
Twenty-three water samples, including seventeen from surface water reservoirs, three from the raw water of groundwater treatment plants, and three from small water systems, were collected in Taiwan and investigated for the presence of, as well as the species of enteroviruses. RT-PCR was used for the detection of enteroviruses. Results revealed that 23.5% of raw water samples from reservoirs were positive for enteroviruses. In addition, one of the three groundwater samples and two of the three small system water samples were positive for enteroviruses. Water samples that were positive for enteroviruses subsequently were evaluated by real-time PCR. The results indicated that enterovirus concentration in groundwater was lower than that in samples obtained from surface water sources. Enteroviruses were identified by nucleic acid sequencing in the 5′-untranslated regions. Three clusters of enteroviruses were identified as coxsackievirus A2, coxsackievirus A6, and enterovirus 71. The presence of enteroviruses indicates the possibility of waterborne transmission of enteroviruses in Taiwan, if water is not adequately treated.
Selinka HC, Botzenhart K, Feuerpfeil I, Puchert W, Schmoll O, Szewzyk R, Willmitzer H. [Detection of viruses in raw water as a basic tool for risk assessment]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. 2011 Apr;54(4):496-504. doi: 10.1007/s00103-011-1249-6. [Article in German]
Human pathogenic viruses may end up in surface waters by fecal contamination. However, the German drinking water ordinance requests that pathogens in drinking water should not be present in concentrations constituting a potential danger to human health. Since many viruses do have a very low dose of infection, they have to be sufficiently eliminated in the process of drinking water purification. Waterborne virus outbreaks in Europe, over the last few decades, were mostly linked to noncompliance with the generally accepted codes of practice for drinking water production. The aimed level of protection of drinking water supplies in Germany, however, exceeds prevention of outbreaks by even protecting against sporadic virus infections. Documentation of such a high level of protection is not achieved by end product control alone but requires a process analysis with risk assessment. To do such an analysis, information regarding the presence of viruses in the raw water used for drinking water production, as well as data of virus elimination rates during purification processes, are of major importance. This paper presents suggestions for implementation of such a risk assessment, focusing on the evaluation of raw water quality.
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Elizabeth Arkhangelsky, Vitaly Gitis. Effect of transmembrane pressure on rejection of viruses by ultrafiltration membranes. Separation and Purification Technology Volume 62, Issue 3, 22 September 2008, Pages 619–628
Although partial penetration of ultrafiltration membranes by viruses and bacteria is well documented, there is no satisfactory explanation for the phenomenon. The current study seeks a possible explanation by studying the retention of viruses at different transmembrane pressures (TMPs). In contrast to previous predictions, higher TMPs lead to reduced virus retention levels. Based on indirect evidences it is proposed that the penetration occurs because of the formation during operation, rather than the initial presence, of abnormally large pores. It is therefore suggested that since pore enlargement is induced by high TMPs, high virus retention levels can be obtained only at low TMP values.
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W Zhang, X Zhang. Adsorption of MS2 on oxide nanoparticles affects chlorine disinfection and solar inactivation Water Research 2015-02-01 69:59-67
Adsorption on colloidal particles is one of the environmental processes affecting fate, transport, viability or reproducibility of viruses. This work studied colloidal interactions (adsorption kinetics and isotherms) between different oxide nanoparticles (NPs) (i.e., TiO2, NiO, ZnO, SiO2, and Al2O3) and bacteriophage, MS2. The results shows that that all oxide NPs exhibited strong adsorption capacity for MS2, except SiO2 NPs, which is supported by the extended Derjaguin and Landau, Verwey and Overbeek (EDLVO) theory. Moreover, the implication of such colloidal interactions on water disinfection is manifested by the observations that the presence of TiO2 and ZnO NPs could enhance MS2 inactivation under solar irradiation, whereas NiO and SiO2 decreased MS2 inactivation. By contrast, all of these oxide NPs were found to mitigate chlorine disinfection against MS2 to different extent, and the shielding effect was probably caused by reduced free chlorine and free MS2 in the solution due to sorption onto NPs. Clearly, there is a pressing need to further understand colloidal interactions between engineered NPs and viruses in water to better improve the current water treatment processes and to develop novel nanomaterials for water disinfection.
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Gerba CP, Abd-Elmaksoud S, Newick H, El-Esnawy NA, Barakat A, Ghanem H. Assessment of Coliphage Surrogates for Testing Drinking Water Treatment Devices. Food and Environmental Virology. 2014 Nov 16.
Test protocols have been developed by the United States Environmental Protection Agency (USEPA) and the World Health Organization (WHO) to test water treatment devices/systems that are used at the individual and home levels to ensure the removal of waterborne viruses. The goal of this study was to assess if coliphage surrogates could be used in this testing in place of the currently required use of animal or human enteric viruses. Five different coliphages (MS-2, PRD1, ΦX-174, Qβ, and fr) were compared to the removal of poliovirus type 1 (LSc-2ab) by eight different water treatment devices/systems using a general case and a challenge case (high organic load, dissolved solids, and turbidity) test water as defined by the USEPA. The performance of the units was rated as a pass/fail based on a 4 log removal/inactivation of the viruses. In all cases, a failure or a pass of the units/system for poliovirus also corresponded to a pass/fail by all of the coliphages. In summary, in using pass/fail criteria as recommended under USEPA guidelines for testing water treatment device/systems, the use of coliphages should be considered as an alternative to reduce cost and time of testing such devices/systems.
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