Article

Presence, infectivity, and stability of enteric viruses in seawater: Relationship to marine water quality in the Florida Keys

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Abstract

Concerns about the presence of enteric viruses in the surface waters of the Florida Keys prompted analyses of virus stability and persistence in these waters. In an in vitro study we evaluated the survival of poliovirus and stability of viral RNA in filtered natural seawater (FSW), unfiltered natural seawater (USW), artificial seawater (ASW) and DI water. This study compared cell culture infectivity with direct reverse transcription-polymerase chain reaction analysis. Attenuated poliovirus was seeded in the above water types and incubated in the dark at 22 and 30 degrees C for 60 days. At 22 degrees C, enhanced poliovirus survival and enhanced detection of viral RNA was observed in the seeded DI water control, artificial seawater and FSW samples. Detection of viruses in unfiltered seawater decreased rapidly at both temperatures by both methods of detection, suggesting that in the natural environment detection of enteroviral RNA may indicate a recent contamination event. In addition, in situ sampling in the Florida Keys during the late winter of 2000 revealed the presence of infectious enteroviruses at two sites and no sites exceeded recommended levels of microbial water quality indicators (enterococci or fecal coliform bacteria).

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... The stability of viruses is variable, some viruses can be very stable and survive long time outside the host (from several days to years), as rotaviruses, while others do not demonstrate the same level of stability, requiring close contact for transmission and being easily destroyed by disinfectants, particularly those that are enveloped (Bosch et al., 2005a;Wetz et al., 2004;Woolhouse et al., 2012). ...
... Another important feature of enteric viruses that pose a great risk to public health is their low infectious dose of less than 10 particles (Carter, 2005;Wetz et al., 2004;Wyn-Jones and Sellwood, 2001). Infections by enteric viruses cause more than 2 million deaths each year (WHO, 2004). ...
... Some authors have considered temperature as the most significant factor in viral survival (Bosch et al., 2006;Yates et al., 1985). Temperature influences the rate at which protein and nucleic acid denaturation occurs, and influences chemical reactions that can degrade the viral capsid and nucleic acids (Bosch et al., 2005a(Bosch et al., , 2008Fong and Lipp, 2005b;Wetz et al., 2004). Accordingly, lower temperatures increase the survival rate of enteric viruses in natural environments (Bosch et al., 2006;Fong and Lipp, 2005b). ...
Thesis
Full-text available
The available classical diagnostic methods, due to many disadvantages, do not allow effective detection of pathogenic enteric viruses in environmental samples. Due to low concentrations of pathogenic viruses in the sea, it is important to develop an effective concentration procedure for their successful detection. In the first part of the doctoral thesis, we focused primarily on the development of a protocol for an effective concentration of pathogenic enteric viruses in coastal water samples. Monolithic chromatographic columns (BIAseparations) were used for the concentration of rotaviruses and noroviruses, prior to the detection with reverse transcription quantitative PCR in real time (RT-qPCR). We tested the efficiency of concentration using columns of various chemical properties and selected pathogenic enteric viruses (rotavirus and norovirus). Among them, hydrophobic interaction monolithic column (CIM® C4) was the most effective. CIM C4 was used to optimize the concentration step and tested in waters with different salinities. The presence of concentrated viruses was confirmed by RT-qPCR and transmission electron microscope. We have developed a protocol that enables rapid concentration of viruses in coastal waters of various salinities and can be used on-site. The presence of RoV and NoV was surveyed, using the developed concentration protocol, prior to one-step RT-qPCR molecular detection, in the inner part of the Bay of Koper, in mussel farming areas and a swimming area. Rotaviruses, noroviruses and fecal indicator bacteria were frequently detected in the inner part of the Bay of Koper. Rotaviruses and noroviruses were detected in the studied area, with higher rates close to the outfall of the wastewater treatment plant in the estuary of river Rižana and were also detected in the middle of the Bay of Koper and in areas used for recreation and mussel farming. The results show that water bodies, which are otherwise defined as suitable for bathing or mussel farming, based on the results of fecal indicator bacteria, still contain low concentrations of pathogenic enteric viruses. In addition to human pathogenic enteric viruses and faecal coliforms, changes in abundance of bacteria and virus particles were studied in relation to temperature, salinity, inorganic and organic nutrient concentrations in the organically polluted Rižana estuary. Preliminary results showed spatially and seasonally changes in bacterial and viral particles abundance, and bacterial composition spatially and seasonally. However, seasonality plays a greater role in bacterial dynamics.
... Gantzer et al. (1998) showed that in seawater, it took 671 days to inactivate 90% of Poliovirus 1 (family Picornaviridae; genus: Enterovirus) and Hepatitis A virus (HAV; family Picornaviridae; genus: Hepatovirus) at 4°C, but only 25 days at 25°C. Wetz et al. (2004) reported that at 22°C, 9.1 days were required for a 90% reduction in poliovirus in filtered seawater, while 3.4 days were required for a similar reduction at 30°C. ...
... Viral persistence in waters can be strongly related to predation by flagellates, extracellular proteases, nucleases, and other enzymes and factors (Fong and Lipp, 2005). Wetz et al. (2004) showed that poliovirus survived much longer in filtered seawater compared to unfiltered seawater at both 22 and 30°C. Similarly, poliovirus RNA was more stable in filtered seawater than in unfiltered seawater at both 4 and 23°C (Tsai et al., 1995). ...
... The RNA of PepMV and PVY in water samples remained detectable using RT-qPCR many weeks after these viruses lost their infectivities (Mehle et al., 2014). Similarly, the persistence of the poliovirus genome in different water samples was shown to be longer than that of infectious polioviruses (Skraber et al., 2004;Wetz et al., 2004), and the degradation of the viral RNA correlated well with the loss of infectivity (Skraber et al., 2004). Staggemeier et al. (2015) showed that while human adenovirus was detected by qPCR in 87.3% of 55 water samples, infectious virus particles were found in only four of these samples (7.3%). ...
Chapter
Viruses represent the most abundant and diverse of the biological entities in environmental waters, including the seas and probably also freshwater systems. They are important players in ecological networks in waters and influence global biochemical cycling and community composition dynamics. Among the many diverse viruses from terrestrial environments found in environmental waters, some are plant, animal, and/or human pathogens. The majority of pathogenic viral species found in waters are very stable and can survive outside host cells for long periods. The occurrence of such viruses in environmental waters has raised concerns because of the confirmation of the infectivity of waterborne viruses even at very low concentrations. This chapter focuses mainly on the survival of human, animal, and plant pathogenic viruses in aqueous environments, the possibility of their water-mediated transmission, the ecological implications of viruses in water, the methods adapted for detecting such viruses, and how to minimize the risk of viruses spreading through water.
... Dilution and transport are closely associated with the water flows. The immobilizations/remobilizations and inactivation and/or mortality of pathogens depend on a multitude of local parameters such as temperature (Murphy, 2017;Bertrand et al., 2012;Wetz et al., 2004), radiation -UV in particular - (Murphy, 2017), suspended particles (sediments, colloids, etc.) and physicochemical characteristics (salinity, pH, dissolved oxygen and redox state of the medium, organic matter, biology …) (Tesson et al., 2018;Kotwal and Cannon, 2014;Lipp et al., 2001;Šolić and Krstuvolic 1992). In certain cases, the immobilization of a pathogen can protect it or, conversely, promote its inactivation: this is particularly the case for certain viruses (Nagvenkar and Ramaiah, 2009;Lipp et al., 2001; which can be protected by biofilms (Skraber et al., 2009), or whose inactivation can be slowed down (Schaub and Sagik, 1975; or accelerated following their adsorption to the surface of certain minerals, in particular metal oxides (Zhuang and Jin, 2008;Murray and Laband, 1979). ...
... , and Cryptosporidium spp. as oocysts (Widmer et al., 2020)); others such as E. coli can multiply under certain conditions (Aruscavage et al., 2006). Temperature affects the fate of pathogens: an increase in temperature promotes the inactivation of human enteric viruses (Dalziel et al., 2016;Bertrand et al., 2012;Wetz et al., 2004) because they increase the risk of denaturing the capsids and genomes of viruses (Tesson et al., 2018). ...
Thesis
Acute gastroenteritis affect between a quarter and a half of people in the World each year. They are responsible for significant morbidity, mortality and healthcare costs. Their direct or indirect transmissions via water, food, air or inert surfaces depend on their aetiology (viral, bacterial or parasitic) and the local context. Bogotá and its region have several specificities: wastewater are often discharged into rivers without or after primary treatment only, the deposit in landfill of toilet papers and diapers soiled by excrement, and the low consumption of fruits and vegetables largely restricted to a handful of relatively cheap products that may be irrigated by surface freshwaters heavily contaminated with faeces. Our PhD aimed to assess the fluxes of some human enteric pathogens in the region of Bogotá and to try to relate these fluxes to the population health. The PhD combined three contributions. First, a method for culturing the human norovirus has been developed using isolated mouse intestinal villi as a cell model exhibiting the full diversity of intestinal epithelial cells. Several concentrations of trypsin were tested to activate noroviruses; the method was applied to faecal and environmental samples. Second, contamination with E. coli and some human enteric pathogens was monitored in water (landfill leachate, runoff water, river, irrigation water, drinking water), leafy vegetables eaten raw (chards) and air (above a landfill, in rural areas, in urban areas) in the Bogotá region. Third, the impact of socioeconomic contexts and individual practices (food, hygiene and health) on cases of acute gastroenteritis was assessed from surveys carried out in one district of Bogotá and analysed by various tools (principal component analysis, modelling …). We have shown that mouse isolated intestinal villi allow the infection and replication of human norovirus. The virus has to be activated with trypsin and has an average replicative cycle of 10 h. Villi are efficient in obtaining abundant biological material and are ideal for studying the biological activity of norovirus or for generating antibodies. They made it possible to see infectious noroviruses not detected by molecular method in several faeces and environmental samples; almost all samples positive by molecular method or immunodot-blot contain infectious noroviruses. At the regional level, the discharges of wastewater in the Bogotá and Balsillas rivers and in Tres Esquinas march contaminate the irrigation network of La Ramada area in the northwest of Bogotá with E. coli and potentially human enteric pathogens. Chards harvested in this area were heavily contaminated, in contrast to other growing areas. Their contamination evolved from their production to their purchase in nearby stores, washings increasing or decreasing their contamination, and handling on the merchant's stalls increasing contamination. The air was often contaminated with E. coli and Shigella spp.; it was not possible to detect a particular contribution of the Doña Juana landfill in pathogen aerosolization. The presence of Shigella spp. was observed in parallel in more than half of the stools of people with diarrhoea. Surveys have shown that the annual frequency of acute gastroenteritis decreases with increasing age; it seemed less common in households with elderly people, possibly due to stricter food hygiene practices. A transmission model of acute gastroenteritis distinguishing contamination from outside the households and contaminations between people in the same households did not show significant differences between neighbourhoods. Used to simulate numerical experiments, it suggests working on much higher numbers of surveys.
... The degradation of PRCV in fresh-and saltwater transit from wastewater to rivers, the ocean and then back to humans via seafood [21,29,30]. Faecal-oral transmission is less common in enveloped viruses, which seem more susceptible to inactivation in aquatic environments and, hence, underrepresented in waterborne virus ...
... Noble and Fuhrman (1997) found that filtration reduces viral decay rates in coastal seawater by 20% on average [18]. They, and others, go on to suggest that heat-labile dissolved organic matter (>30 kDa), extracellular proteases and nucleases from microorganisms are key contributors-second only to UV-C degradation-of viral decline in coastal ecosystems [17,18,30,47]. Heatlabile, high-MW molecules and colloids between 30 kDa and 0.2 μm were found to be responsible for about 20 to 25% degradation of marine phages [18]. ...
Article
Coronaviruses (CoVs) are a family of viruses that are best known as the causative agents of human diseases like the common cold, Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS) and COVID-19. CoVs spread by human-to-human transmission via droplets or direct contact. There is, however, concern about potential waterborne transmission of SARS-CoV-2, the virus responsible for COVID-19, as it has been found in wastewater facilities and rivers. To date, little is known about the stability of SARS-CoV-2 or any other free coronavirus in aquatic environments. The inactivation of terrestrial CoVs in seawater is rarely studied. Here, we use a porcine respiratory coronavirus (PRCV) that is commonly found in animal husbandry as a surrogate to study the stability of CoVs in natural water. A series of experiments were conducted in which PRCV (strain 91V44) was added to filtered and unfiltered fresh- and saltwater taken from the river Scheldt and the North Sea. Virus titres were then measured by TCID50-assays using swine testicle cell cultures after various incubation times. The results show that viral inactivation of PRCV in filtered seawater can be rapid, with an observed 99% decline in the viral load after just two days, which may depend on temperature and the total suspended matter concentration. PRCV degraded much slower in filtered water from the river Scheldt, taking over 15 days to decline by 99%, which was somewhat faster than the PBS control treatment (T99 = 19.2 days). Overall, the results suggest that terrestrial CoVs are not likely to accumulate in marine environments. Studies into potential interactions with exudates (proteases, nucleases) from the microbial food web are, however, recommended.
... The degradation of PRCV in fresh-and saltwater transit from wastewater to rivers, the ocean and then back to humans via seafood [21,29,30]. Faecal-oral transmission is less common in enveloped viruses, which seem more susceptible to inactivation in aquatic environments and, hence, underrepresented in waterborne virus ...
... Noble and Fuhrman (1997) found that filtration reduces viral decay rates in coastal seawater by 20% on average [18]. They, and others, go on to suggest that heat-labile dissolved organic matter (>30 kDa), extracellular proteases and nucleases from microorganisms are key contributors-second only to UV-C degradation-of viral decline in coastal ecosystems [17,18,30,47]. Heatlabile, high-MW molecules and colloids between 30 kDa and 0.2 μm were found to be responsible for about 20 to 25% degradation of marine phages [18]. ...
Article
To date, few studies have examined the role of sea spray aerosols (SSAs) in human exposure to harmful and beneficial marine compounds. Two groups of phycotoxins (brevetoxins and ovatoxins) have been reported to induce respiratory syndromes during harmful algal blooms. The aerosolization and coastal air concentrations of other common marine phycotoxins have, however, never been examined. This study provides the first (experimental) evidence and characterization of the aerosolization of okadaic acid (OA), homoyessotoxin, and dinophysistoxin-1 using seawater spiked with toxic algae combined with the realistic SSA production in a marine aerosol reference tank (MART). The potential for aerosolization of these phycotoxins was highlighted by their 78- to 1769-fold enrichment in SSAs relative to the subsurface water. To obtain and support these results, we first developed an analytical method for the determination of phycotoxin concentrations in SSAs, which showed good linearity (R2 > 0.99), recovery (85.3-101.8%), and precision (RSDs ≤ 17.2%). We also investigated natural phycotoxin air concentrations by means of in situ SSA sampling with concurrent aerosolization experiments using natural seawater in the MART. This approach allowed us to indirectly quantify the (harmless) magnitude of OA concentrations (0.6-51 pg m-3) in Belgium's coastal air. Overall, this study provides new insights into the enriched aerosolization of marine compounds and proposes a framework to assess their airborne exposure and effects on human health.
... Furthermore, environmental factors like temperature and ultraviolet radiation can affect the stability of these viruses in seawater by damaging the viral nucleic acid and proteins. In addition, water salinity, which is quite high in the region, can cause viral aggregation and hence lower viral titers [40]. Furthermore, the study area is characterized by high organic matter pollution from the continuous disposal of inadequately treated sewage, so it is highly probable that high concentrations of extracellular proteases, nucleases, and other enzymes could damage the virus capsid and result in genome degradation [23,40]. ...
... In addition, water salinity, which is quite high in the region, can cause viral aggregation and hence lower viral titers [40]. Furthermore, the study area is characterized by high organic matter pollution from the continuous disposal of inadequately treated sewage, so it is highly probable that high concentrations of extracellular proteases, nucleases, and other enzymes could damage the virus capsid and result in genome degradation [23,40]. Our negative results could also be a consequence of the presence of high concentrations of PCR or RT inhibitory substances in seawater [12]. ...
Article
Full-text available
The incidence of enteric viruses in treated wastewater and their potential release into the environment or use for agriculture are very critical matters in public health. In our study, PCR (polymerase chain reaction) analysis of enteric viruses was performed on 59 samples of influents and effluents collected from Tubli wastewater treatment plant (Water Pollution Control Center (WPCC)) and Tubli Bay, where the effluents were discharged, in Kingdom of Bahrain during two sampling periods. Four clinically essential waterborne enteric viruses were examined: enterovirus (EV), hepatitis A virus (HAV), astroviruses (AV), and rotaviruses (RV) and compared to standard bacterial and bacteriophages indicators of fecal pollution. Detection rates of EV, AV, HAV, and RV in the influent samples were 100%, 75%, 12.5%, and 12.5%, respectively, while 50% of the effluent samples from Tubli WPCC contained only EV RNA. None of the tested enteric viruses could be detected in any of the samples collected directly from Tubli Bay. Effluent samples from Tubli plant did not show significant seasonal differences. Since detection of enteric viruses genome does not necessarily indicate infectivity, the infectivity of these viruses was evaluated through isolation and growth of indictor bacteria and bacteriophages. High concentration of fecal bacteriological indicators was detected in all effluents samples (100%): 3.20 × 10 3 cfu/mL for E. coli, 1.32 × 10 3 cfu/mL for Salmonella spp., and 1.92 × 10 3 cfu/mL for Shigella spp. E. coli and Salmonella specific bacteriophages were also detected in the effluent samples in high titers. The combined results of PCR and bacterial enumeration point to a probable public health risk via the use of these wastewaters in agriculture or their discharge into the sea. Continuous surveillance of viral and bacterial prevalence and their resistance to sewage disinfection procedures could contribute to a better control of risks associated with the recycling of effluent wastewater and its release into the environment.
... [63] Table 2 lists general FIB and pathogen relationships reported in the datasets analyzed for marine and brackish waters. Of the 29 studies reviewed, almost half (n = 13) did not report statistical analysis of the relationships [52,[76][77][78][79][80][81][82][83][84][85][86][87]. Within the remaining studies, ten did not find a relationship [64,70,[88][89][90][91][92][93][94][95] while six reported a positive relationship between at least one indicator and one pathogen [59,[96][97][98][99][100]. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater (17 vs. 44) and the proportion of statistically significant relationships (compared to non-significant) was considerably higher in freshwater (Fisher's exact test, p < 0.0001). ...
... In marine and brackish waters, approximately, half of studies (n = 6) did not report any statistical analysis [76,77,81,82,87,89], while three reported statistically significant relationships [79,90,100], and five reported non-significant relationships [64,88,91,92,94]. Two studies found significant relationships between F-specific coliphage and pathogens; one reported it with methicillin resistant S. aureus (MRSA), and S. aureus at a marine beach affected by fecal-impacted freshwater intrusion [79], while a second reported it for adenoviruses in water impacted by urban run-off [90] (Table 3). ...
Article
Full-text available
Fecal pollution of recreational waters can cause scenic blight and pose a threat to public health, resulting in beach advisories and closures. Fecal indicator bacteria (total and fecal coliforms, Escherichia coli, and enterococci), and alternative indicators of fecal pollution (Clostridium perfringens and bacteriophages) are routinely used in the assessment of sanitary quality of recreational waters. However, fecal indicator bacteria (FIB), and alternative indicators are found in the gastrointestinal tract of humans, and many other animals and therefore are considered general indicators of fecal pollution. As such, there is room for improvement in terms of their use for informing risk assessment and remediation strategies. Microbial source tracking (MST) genetic markers are closely associated with animal hosts and are used to identify fecal pollution sources. In this review, we examine 73 papers generated over 40 years that reported the relationship between at least one indicator and one pathogen group or species. Nearly half of the reports did not include statistical analysis, while the remainder were almost equally split between those that observed statistically significant relationships and those that did not. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater, and the number of statistically significant relationships was considerably higher in freshwater (p < 0.0001). Overall, significant relationships were more commonly reported between FIB and pathogenic bacteria or protozoa, compared to pathogenic viruses (p: 0.0022–0.0005), and this was more pronounced in freshwater compared to marine. Statistically significant relationships were typically noted following wet weather events and at sites known to be impacted by recent fecal pollution. Among the studies that reported frequency of detection, FIB were detected most consistently, followed by alternative indicators. MST markers and the three pathogen groups were detected least frequently. This trend was mirrored by reported concentrations for each group of organisms (FIB > alternative indicators > MST markers > pathogens). Thus, while FIB, alternative indicators, and MST markers continue to be suitable indicators of fecal pollution, their relationship with waterborne pathogens, particularly viruses, is tenuous at best and influenced by many different factors such as frequency of detection, variable shedding rates, differential fate and transport characteristics, as well as a broad range of site-specific factors such as the potential for the presence of a complex mixture of multiple sources of fecal contamination and pathogens.
... A wide range of methods has been developed and used to recover viruses from various types of environmental waters (Casas and Sunen, 2002;Katayama et al., 2002;Lambertini et al., 2008;Nordgren et al., 2009;Rodriguez-Diaz et al., 2009;Bennett et al., 2010;Leskinen et al., 2010). Virus adsorption and elution (VIRADEL) methods such as negatively charged HA membranes (Katayama et al., 2002;Haramoto et al., 2005), positively or negatively charged 1MDS cartridge filters (Lukasik et al., 2000), filterite filters (Wetz et al., 2004), electropositive nanoCeram filters (Lee et al., 2011) andglass wool (Lambertini et al., 2008) have been most commonly used to recover viruses from environmental waters. The mechanisms of these methods have been described in a review paper (Wong et al., 2012). ...
... None of the field studies reported the presence of viral markers in soils and sediments. It is well known that these environmental matrices may harbour enteric viruses and other faecal microorganisms (Wheeler et al., 2003;Staggemeier et al., 2015). Viruses associated with particular matter in suspension or solid matrices tend to remain viable for a longer time than if they were dispersed in water (Schenewski and Julich, 2001). ...
... Aichi virus and Parechovirus) in sewage-polluted coastal waters, i.e. ENVS; (iv) molecular typing methods based on RT-PCR and nucleotide sequencing of portions of the VP1 gene (i.e., direct genotyping identification) can be used to obtain locationspecific data on enterovirus serotypes in coastal waters, which is of practical value in epidemiological surveillance and in outbreak investigation as previously mentioned; and (v) most frequently EV concentrations in marine waters are not correlated with concentrations of bacterial indicators of sewage pollution as previously documented, although the simultaneous occurrence of EVs and fecal indicator bacteria in water quality monitoring can be used in most geographical settings as a reasonable indication of recent fecal contamination and therefore of chronic pollution problems in coastal waters (Betancourt et al., 2015;Boehm et al., 2003;Connell et al., 2012;Donaldson et al., 2002;Fuhrman et al., 2005;Gersberg et al., 2006;Gregory et al., 2006;Lipp et al., 2001b;Lipp et al., 2001c;Moce-Llivina et al., 2005;Wetz et al., 2004;Wyer et al., 1995). ...
... The T90 and T99 decay rates for infectivity and viral RNA genome detection of poliovirus strain Lsc-1 was 2 and 4 days, respectively, in unfiltered natural seawater at 30°C, while it was 2.2 and 4.4 days, respectively at 22°C in unfiltered natural seawater (Wetz et al., 2004). Longer time periods (lower rates of virus inactivation) were documented for filtered seawater and distilled water indicating that much of the virus decay was caused by factors biological in nature (i.e., microbial activity). ...
Chapter
Enteroviruses (EVs), including poliovirus and nonpolio enteroviruses (i.e., coxsackieviruses, echoviruses, enteroviruses) are among the most common genera of the Picornaviridae family that infect humans and therefore are known to circulate widely in human populations throughout the world. New genera of the Picornaviridae family (i.e., Saffold cardiovirus [SAFV]) Cosavirus [common stool-associated picornavirus] Salivirus [stool Aichi-like virus]) have been identified in fecal specimens and wastewaters using conventional and highly-sensitive genomic sequencing technologies. In addition, members of the Echovirus genus originally known as echovirus 22 and 23 have been reclassified within the genus Parechovirus. Likewise, previous rhinovirus species have been reclassified within the Enterovirus genus. Enterovirus (EV) infections are a significant cause of morbidity and mortality throughout the world, primarily in infants and young children. Nevertheless, reliable worldwide estimates of EV-related mortality are not currently available. Enteroviruses like most enteric viruses have evolved stability to adverse environmental conditions, including thermal stability, acid stability, resistant to radiation as well as to oxidants and proteolytic enzymes, which allow survival of these viruses in the environment and facilitate their transmission through multiple environmental routes (e.g., water, food, aerosols, and virus-contaminated inanimate objects or fomites). Human wastes, such as sewage and poorly treated effluents, urban stormwater and combined sewers overflows (CSO) are the primary source of enteroviruses released into aquatic and land environments that subsequently contaminate raw source waters for potable supply, bathing waters, shellfish waters, and waters used for irrigation of crops. Groundwater sources are also vulnerable to contamination with enteroviruses through different routes including direct injection of wastes through wells, percolation of sewage sprayed over the land, leaking or broken sewer lines, seepage from waste lagoons, infiltration of sewage-polluted surface streams, and septic tank effluents. The biophysical properties of enteroviruses (i.e., small-size, genome type and the non-enveloped capsid structure of the virion) play an important role on virus survival in the environment and on the physical removal and inactivation of virus particles through conventional wastewater treatment processes. Membrane bioreactor systems (MBRs) are becoming increasingly applied in developed regions as advanced wastewater treatment technologies to produce treated effluents of very high quality applicable to wastewater discharge and recycling solutions, including non-potable or indirect potable reuse. The distribution and persistence of enteroviruses in sewage-polluted waters may vary geographically depending on the epidemiological status of the population, population density, and the extent of sanitation coverage (i.e., wastewater treatment and wastewater disposal) which influence the viral load released into the environment. Recent estimates by the World Health Organization (WHO)/United Nations Children’s Fund (UNICEF) Joint Monitoring Programme for Water Supply and Sanitation indicate that despite significant progress on sanitation, in 2012, more than one third of the global population - some 2.5 billion people – do not use an improved sanitation facility, and of these 1 billion people still practice open defecation. Sewage represents a useful matrix to derive information on circulating enteroviruses in given populations and to describe the enterovirus epidemiology associated with human disease, also known as environmental surveillance. Environmental poliovirus surveillance is a major goal of the WHO Global Poliovirus Eradication Initiative (GPEI) used to monitor pathways of poliovirus transmission of wild poliovirus and circulating vaccine-derived polioviruses (cVDPVs). A major effort to develop new, improved, and safer live polio vaccine is being promoted by the WHO, Rotary and the Bill & Melinda Gates Foundation. Human enteroviruses have been recovered worldwide from surface waters including coastal waters, rivers streams, and lakes, from ground waters, wastewaters and finished drinking water. Numerous methodological approaches have been recently developed for concentration of human enteric viruses from water and their isolation from the environment. Selection of an appropriate filtration method for the primary concentration of viruses is crucial to successful virus detection. However, an efficient method to recover all viruses has not been developed yet. Integrated cell culture and PCR (ICC-PCR) developed in the late 1980s is still applicable for detection and identification of a suite of infective viral pathogens recovered from environmental samples. The detection of enteroviruses in sources of drinking water and recreational water bodies has been broadly accepted as a marker of a possible failure of the sanitation systems and as an indicator of the potential role of water in disease outbreaks. Moreover, since the natural host for all human enteroviruses is humans, the detection and quantification of amplifiable enterovirus genetic material in environmental waters has been proposed and successfully used as a water quality assessment tool for tracking sources of human fecal pollution.
... The effect of these factors changed according to the type of environment (Rzeżutka and Cook, 2004; Pinon and Vialette, 2018). Enteric viruses in the soil can persist for more than 100 days at 20 to 30°C, up to 120 days in fresh water and sewage, and up to 130 days in seawater(Wetz et al., 2004).Kocwa-Haluch (2001) showed that with a wide range of pH (3 to 10) and low degrees of temperatures enteric viruses can persist for a long time. Rotavirus is one of the more persistent viruses in aquatic environments; it can survive for 16 days with a 2-log 10 reduction in the initial count, using cell-based techniques for the detection of the virus in unpolluted lake water(Pancorbo et al., 1987). ...
Article
Full-text available
This review was presented to suggest if viruses could be used as fecal indicators for drinking water and treated sewage pollution. The failure of bacterial indicators in a lot of cases to indicate viral pollution in drinking water and treated sewage indicates that bacterial indicators may fail to express fecal pollution in drinking water and treated sewage. We could explain this statement as viruses, especially enteric viruses are generally secreted in the feces of infected or carrier persons. Thus, it always expresses the fecal contamination in sewage and consequently water. Hence, the defect of bacterial indicators to indicate the enteric virus’s presence in a lot of cases may indicate failure in expressing the fecal pollution, which is the cause of viral contamination of sewage and water. Adding at least one viral indicator besides bacterial indicators can help supply more perfect water quality results and greater assurance of water quality safety. Adenoviruses and bacteriophages may represent suitable candidates as indices of viral and fecal pollution indicators in drinking water and treated sewage samples
... Also Griffin et al. (2000) realized that more 90% of canals and near waters from 19 locations that poured to the Florida Keys have been positive tests for at least one group of enteroviruses. Interestingly, Wetz et al. evaluated the persistence of Poliovirus in different types of seawater at Florida Keys and found that temperature, concentration of pathogen/salt, and type of seawater play significant role in inactivation the pathogen ( Wetz et al., 2004 ). Furthermore, in the context of COVID19, the SARS-CoV-2 can easily enter to oceans/seawater and contaminated the aquatic environment. ...
Article
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The unprecedented situation of the COVID-19 pandemic heavily polluted water bodies whereas the presence of SARS-CoV-2, even in treated wastewater in every corner of the world is reported. The main aim of the present study is to show the effectiveness and feasibility of some well-known desalination technologies which are reverse osmosis (RO), Electrodialysis (ED), Membrane Distillation (MD), multi effect distillation (MED), and multi stage flashing (MSF) during the COVID-19 pandemic. Systems’ effectiveness against the novel coronavirus based on three parameters of nasopharynx/nasal saline-irrigation, temperature of operation and pretreatment methods are evaluated. First, based on previous clinical studies, it showed that using saline solution (hypertonic saline >0.9% concentration) for gargling/irrigating of nasal/nasopharynx/throat results in reducing and replication of the viral in patients, subsequently the feed water of desalination plants which has concentration higher than 3.5% (35000ppm) is preventive against the SARS-CoV-2 virus. Second, the temperature operation of thermally-driven desalination; MSF and MED (70-120°C) and MD (55-85°C) is high enough to inhibit the contamination of plant structure and viral survival in feed water. The third factor is utilizing various pretreatment process such as chlorination, filtration, thermal/precipitation softening, ultrafiltration (mostly for RO, but also for MD, MED and MSF), which are powerful treatment methods against biologically-contaminated feed water particularly the SARS-CoV-2. Eventually, it can be concluded that large-scale desalination plants during COVID-19 and similar situation are completely reliable for providing safe drinking water.
... Microbial DNases and RNases secreted by the living or dead cells also cause significant damage to the nucleic acids and thereby hamper detection (Palchevskiy and Finkel, 2009). In environmental samples, the microbial metabolism contributes to a great extent for the degradation of the nucleic acids and therefore is a major factor deciding its stability during detection procedures (Tsai et al., 1995;Deere et al., 1996;Wetz et al., 2004). DNA stability increases under dry conditions, low temperatures and in the absence of microbial activity and oxygen (Lorenz and Wackernagel, 1994). ...
... Microbial DNases and RNases secreted by the living or dead cells also cause significant damage to the nucleic acids and thereby hamper detection (Palchevskiy and Finkel, 2009). In environmental samples, the microbial metabolism contributes to a great extent for the degradation of the nucleic acids and therefore is a major factor deciding its stability during detection procedures (Tsai et al., 1995;Deere et al., 1996;Wetz et al., 2004). DNA stability increases under dry conditions, low temperatures and in the absence of microbial activity and oxygen (Lorenz and Wackernagel, 1994). ...
... In addition, this study provides the first report of the presence of AiV in SGDs in a tropical setting in Mexico, in concentrations from 10 2 to 10 6 GC/L, a range previously reported to occur in groundwater from different aquatic environments ( Gersberg et al., 2006;Machain-Williams et al., 2014;Sassoubre et al., 2012), our study indicated that the levels of these viruses were below the LoD in all the SGD samples tested. It has been suggested that due to their low persistence in the marine environment, EVs might be better indicators of recent contamination (Futch et al., 2010;Wetz et al., 2004); however, a more intensive spatialtemporal study should be conducted in unique water environments, such as SGDs to test this hypothesis. ...
Article
The occurrence of fecal microorganisms such as total coliforms (TC), Escherichia coli (E. coli), coliphages (somatic and F+ specific), and the genomes of fecal viruses: human adenovirus (HAdV), norovirus (NoV) genogroup I (GI) and II (GII), enterovirus (EV), aichi virus (AiV) and Pepper mild mottle virus (PMMoV) was explored in submarine groundwater discharges (SGDs) in the Mexican Caribbean. Ultra‐filtrated water samples were subjected to nucleic acid extraction and real time quantitative PCR. Results showed the presence of TC bacteria at all sites, while the detection of E. coli occurred only during the dry season. Coliphages occurred during the rainy and dry seasons, with concentrations ranging from 10 to 2,560 plaque forming units (PFU/100 ml). HAdV and AiV were detected in 50% and 41% of the samples, at concentrations ranging from 102 to 104 genome copies per liter (GC/L) and from 102 to 106 GC/L, respectively. NoV GI and II were detected in 25% and 16% of the samples, at concentrations of 101 GC/L and 102 to 103 GC/L, respectively. PMMoV was detected in 50% of the samples at concentrations ranging from 101 to 103 GC/L. The EV genomes were not detected. These findings demonstrate that fecal microorganisms can be transported through SGDs in the Mexican Caribbean, potentially contributing to human health risks for recreation.
... A direct link between nutrient load in the water column and GAs has not yet been proven [50], but if GAs can be induced by microbial invasions these lesions may be more severe in the presence of pollution. Similarly the role of viruses in GA etiology has not yet been investigated despite being associated with tumor formation in other animals [65][66][67] and correlation with human population density [68][69][70]. As such, the importance of the holobiont in coral GA formation remains an area of research still requiring extensive investigation. ...
Article
One of the most widespread coral diseases linked to anthropogenic activities and recorded on reefs worldwide is characterized by anomalous growth formations in stony corals, referred to as coral growth anomalies (GAs). The biological functions of GA tissue include limited reproduction, reduced access to resources, and weakened ability to defend against predators. Transcriptomic analyses have revealed that, in some cases, disease progression can involve host genes related to oncogenesis, suggesting that the GA tissues may be malignant neoplasms such as those developed by vertebrates. The number of studies reporting the presence of GAs in common reef-forming species highlights the urgency of a thorough understanding of the pathology and causative factors of this disease and its parallels to higher organism malignant tissue growth. Here, we review the current state of knowledge on the etiology and holobiont features of GAs in reef-building corals.
... Typically, the decay experiments were conducted in natural surface water or wastewater that was collected from wastewater treatment facilities (Booncharoen et al., 2018;Casanova and Weaver, 2015;Jeanneau et al., 2012;Maluquer de Motes et al., 2008;Ye et al., 2016). Sometimes, fresh water or seawater were spiked with wastewater (Ahmed et al., 2018;Ahmed et al., 2019b) or fecal material (Wanjugi et al., 2016), or seeded with cultured strains (Charles et al., 2008;Nayak et al., 2015;Wetz et al., 2004) at the beginning of the decay experiments. The persistence of pathogen infectivity or genetic material (nucleic acid) was subsequently recorded by measuring the remaining concentration in tested water during the experimental period (Rigotto et al., 2011;Seitz et al., 2011). ...
Article
Measurement of pathogens in raw wastewater from a population within certain sewer catchments can provide quantitative information on public health status within the sampled urban area. This so-called wastewater-based epidemiology (WBE) approach has the potential of becoming a powerful tool to monitor pathogen circulation and support timely intervention during outbreaks. However, many WBE studies failed to account for the pathogen decay during wastewater transportation in back calculating the disease prevalence. Various sewer process factors, including water temperature and infiltration/inflow, can lead to the variation of pathogen decay rates. This paper firstly reviewed the effects of temperature and types of water, i.e., wastewater, freshwater, and saline water, on the decay of four selected enteric pathogens, i.e., Campylobacter, Salmonella, Norovirus, and Adenovirus. To elucidate the importance of the pathogen decay rates (measured by culture and molecular methods) to WBE, a sensitivity analysis was conducted on the back-calculation equation for infection prevalence with decay rates collected from published literature. It was found that WBE back-calculation is more sensitive to decay rates under the condition of high wastewater temperature (i.e., over 25 °C) or if wastewater is diluted by saline water (i.e., sewer infiltration or use of seawater as an alternative source of freshwater constituting around 1/3 household water demand in some cities). Stormwater dilution of domestic wastewater (i.e., sewer inflow might achieve 10 times volumetric dilution) was shown to play a role in increasing the sensitivity of WBE back-calculation to bacterial pathogens, but not viral pathogens. Hence, WBE back-calculation in real sewers should account for in-sewer decay of specific pathogen species under different wastewater temperatures and dilutions. Overall, this review contributes to a better understanding of pathogen decay in wastewater which can lead to improved accuracy of WBE back-calculation.
... The stability of enteric viruses is more greatly affected in environments with higher salinity, such as in marine or brackish waters (Moresco et al., 2015;Wetz et al., 2004). The aggregation of transparent exopolymer particles (TEP), a type of exopolymeric substance (EPS) generated by bacteria, is directly correlated to increasing salinity levels, and higher rates of MNV-1 genome recovery from TEP aggregates has been shown (Hanley et al., 2018). ...
Article
The public health significance of plastics and microplastics in different environmental matrices has mainly focused on the toxicological effects of human ingestion. But these pollutants can also harbour pathogenic bacteria as the surfaces of plastics in the environment quickly become colonised by microbial biofilm. This novel microbial habitat has been termed the 'plastisphere' and could facilitate the survival and dissemination of important bacterial and fungal pathogens. Importantly, however, the role of plastic pollution as a secondary pathway for the transmission of human pathogenic viruses has never been addressed. Due to the high prevalence of both enteric and respiratory viruses in the population and in the environment, there is significant potential for human viruses to become associated with the plastisphere. In this review we critically evaluate current knowledge on the interaction of human enteric and respiratory viruses with plastic surfaces and identify the main environmental conditions and plastic characteristics that could affect virus survival and persistence in the environment. Our hypothesis is that the plastisphere can enhance the adhesion, survival and dissemination of human pathogenic viruses and potentially lead to more effective transfer and transmission of viral diseases within the environment. We identify key research questions needed to more fully assess the potential human health risks associated with viruses on plastic surfaces. These include understanding, (1) the mechanisms of viral attachment to either naked or biofilm-colonised plastic (2) how the structural characteristics of viruses (e.g., enveloped, or non-enveloped), affect their persistence in the plastisphere, (3) whether the plastisphere offers protection and increases the persistence of infectious viruses in soil, freshwater, and marine environments.
... With a broad range of pollutants and abundant microbial presence, sewers function as 'microbial reactors' where substances are transformed and degraded based on their chemical and biological reactivity [56]. Generally, for most viruses, the water matrix plays an important role in their inactivation and decay [57]. Without active human cells as hosts in wastewater, the infectivity of SARS-CoV-2 was reported to be reduced by 90% in several minutes to 2.1 days in wastewater environment, however, its RNA was significantly more persistent, reaching 3-33 days [58]. ...
Article
Wastewater-based epidemiology (WBE) is a promising approach for estimating population-wide COVID-19 prevalence through detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater. However, various methodological challenges associated with WBE would affect the accuracy of prevalence estimation. To date, the overall uncertainty of WBE and the impact of each step on the prevalence estimation are largely unknown. This study divided the WBE approach into five steps (i.e., virus shedding; in-sewer transportation; sampling and storage; analysis of SARS-CoV-2 RNA concentration in wastewater; back-estimation and further summarized and quantified the uncertainties associated with each step through a systematic review. Although the shedding of SARS-CoV-2 RNA varied greatly between COVID-19 positive patients, with more than 10 infected persons in the catchment area, the uncertainty caused by the excretion rate became limited for the prevalence estimation. Using a high-frequency flow-proportional sampling and estimating the prevalence through actual water usage data significantly reduced the overall uncertainties to around 20-40% (relative standard deviation, RSD). And under such a scenario, the analytical uncertainty of SARS-CoV-2 RNA in wastewater was the dominant factor. This highlights the importance of using surrogate viruses as internal or external standards during the wastewater analysis, and the need for further improvement on analytical approaches to minimize the analytical uncertainty. This study supports the application of WBE as a complementary surveillance strategy for monitoring COVID-19 prevalence and provides methodological improvements and suggestions to enhance the reliability for future studies.
... Therefore, the high and prolonged rainfall events in the Korean peninsula in summer could affect the high concentrations and occurrences of coliphages in water samples. Moreover, salinity can have significant effects on the presence and concentration of coliphages in seawater samples, as previously described (Wetz et al. 2004). Due to their significant effects on coliphage concentrations, extensive measurements of environmental factors should be considered when tracking water samples. ...
Article
Full-text available
Human and animal feces are important sources of various types of microbial contamination in water. Especially, enteric viruses, the major agents of waterborne infection, can attain long-term survival in water environments due to their strong resistance to various environmental factors including pH, salinity, and temperature. Coliphages are promising viral indicators for fecal contamination in water environments. Here, we investigated the seasonal and spatial distribution of male-specific and somatic coliphages in surface water and seawater at three major aquaculture areas, including Goseong Bay, Aphae Island, and Gomso Bay, in Republic of Korea over a period of 1 year. We selected 6 surface water and 14 seawater sampling sites for each study area and collected a total of 480 water samples from March 2014 to February 2015. Overall, surface water samples contained higher occurrences of coliphages than seawater samples. The high coliphage concentrations were detected in spring (March to May 2014). The differences in geographical features and patterns in land usage of the three aquaculture areas may have affected the coliphage concentration and occurrence. Moreover, environmental factors such as cumulative precipitation were strongly correlated with coliphage concentrations. Therefore, we suggest that further longitudinal studies on coliphage concentrations and distributions should be performed to support the application of coliphages in tracking fecal contamination in water.
... However, recent studies have reported correlations between detection of virus genomes and infectivity under some specific conditions. From studies of the duration of detection by PCR in seawater, enterovirus was suggested as a useful indicator of recent contamination events (Wetz et al. 2004); however, the results were dependent on the water type, with greater stability in sterile waters resulting in detection by PCR after no infectious viruses were detectable. For astrovirus and rotavirus, correlations between the concentrations of infectious viruses and of the viral genomes were reported in surface water exposed to light; whereas, in groundwater (not exposed to light), viral genomes were more stable than infectious viruses (Espinosa et al. 2008). ...
... Stability of the virus in external environmental conditions depends on temperature, humidity, and UV radiations. Exposure to daylight for 24 h has led to inactivation of 99.9% of PV [1,27,28]. A study conducted by Lodder et al. demonstrated that the local sewage which is being discarded into the river mass in Holland had very high density of enterovirus particles [23]. ...
Article
Full-text available
Background The Enterovirus (EV) surveillance system is inadequate in densely populated cities in India. EV can be shed in feces for several weeks; these viruses are not easily inactivated and may persist in sewage for long periods. Surveillance and epidemiological study of EV-related disease is necessary. Methods In this study, we compare the EV found in sewage with clinically isolated samples. Tissue culture was used for isolation of the virus and serotype confirmed by enterovirus neutralization tests. Results We found positive cases for enterovirus from clinical and sewage samples and identified additional isolates as echovirus 9, 11, 25 & 30 by sequencing. Conclusion There is a close relation among the serotypes of enterovirus shed in stools and isolated from the environment but few serotypes which were detected in sewage samples were not found clinically and the few which were detected clinically not found in sewage because some viruses are difficult to detect by the cell culture method.This study will be helpful for the researchers who are working on polio and nonpolio enterovirus especially in the countries which are struggling for polio eradication.
... Our findings agreed with another study carried out by PEDLEY et al. 2006 which demonstrated that the stability of viruses is known to be greater in specific conditions: low temperatures, absence of light and limited predatory populations. Regarding the natural predation of the microbiota, WETZ et al. (2004) demonstrated that polioviruses can survive longer in filtered than unfiltered seawater. In conclusion, the nature of samples is a critical issue that could affect the activity of indigenous micro-organisms and their virucidal activity, as well as the production of ROS, which ultimately influences decay rates of enteric viruses regardless of the effect of natural sunlight. ...
... Viruses are stable at low temperatures, while denaturation of the viral proteins occurs at temperatures higher than 100°C (Lipp et al. 2001). Acidic pH and water salinity have the greatest impact on the viral inactivation (Wetz et al. 2004). ...
Article
Full-text available
This study comprises the first systematic survey of the occurrence of Norovirus in Mediterranean mussels from harvesting areas in Montenegro coast of Adriatic Sea. Mussels may accumulate contaminants of public health concern, including pathogenic bacteria and viruses. Microbiological monitoring of harvesting areas is based on count of Escherichia coli in bivalve molluscs in the European Union. It is assumed that E. coli does not reflect contamination with enteric viruses. A structured field study was undertaken at six locations in Bay of Kotor, Montenegro, in order to investigate plausible influence of environmental factors on the variability of E. coli and norovirus (NoV). From July 2015 to July 2016, a total of 72 samples of mussels were collected in coastal harvesting areas of the Montenegro. The samples were screened for NoV of genogroups GI and GII using reverse transcription-qPCR (RT-qPCR). There were 43% NoV positive samples with higher presence of genogroup GII (74.2%). With regard to influence of environmental conditions on Norovirus presence, we have proved seasonal pattern of virus occurrence i.e., the largest number of positive samples was noticed during winter, while other physico-chemical factors were not of great significance. It was found that count of E. coli did not correlate with Norovirus prevalence. From the aspect of food safety, an upgrade of monitoring plans could lead to obtaining safer products.
... more countries consider the development of marine resources as increasingly important. The on-site detection of marine organisms, environmental pollutants and other materials such as the mineral matter will play an important role in ocean research (Delaney et al. 2008;Duffy et al. 2013; Thomsen et al. 2012;Wetz et al. 2004). Removing samples from the sea can alter their composition making analysis invalid. ...
Article
Full-text available
More than 71% of the earth’s surface area is occupied by ocean, and the shipping has become one of the most common forms of transportation. There are many applications for rapid on-site detection in ships and marine engineering in general. However, owing to the limited space and environmental conditions, large-scale laboratory equipment cannot be utilized on ships and offline examination methods cannot meet the needs for rapid detection and analysis of problems. Microfluidic technologies provide an excellent platform where various biological and chemical reactions can be completed on very small microfluidic chips. The combination of microfluidic technologies and ship and marine engineering will have important theoretical significance and practical value. These applications mainly include ballast water analysis, lubricating oil analysis, monitoring oil spill, ship exhaust gas detection and ship sewage detection. Therefore, in this paper, we have summarized the current applications of microfluidic technologies in ships and marine engineering and suggested prospects for the potential research directions in the future. Keywords Microfluidic technology, Ballast water, Lubricating oil, Oil spilling, Ships’ exhaust gas, Ship sewage
... EVs are highly resistant in several environments and able to preserve their infectivity for months (Wetz et al., 2004;Fong and Lipp, 2005;Rajtar et al., 2008), which reflects their widespread occurrence in populations (Sellwood et al., 1981;Hovi et al., 1996;Sedmark et al., 2003). As other enteric viruses, they can contaminate soil, food crops and natural watercourses through the discharge of contaminated wastewater. ...
Chapter
In Tunisia, the expansion of irrigated area and the semiarid climate make it compulsory to adopt strategies of water management to increase water use efficiency. Subsurface drip irrigation (SDI), providing the application of high frequency small irrigation volumes below the soil surface have been increasingly used to enhance irrigation efficiency. Deficit irrigation has shown successful results with a large number of crops in various countries. Objective of this paper was to assess the effects of deficit irrigation on gross margin and water use efficiency of potatoes crop, irrigated with subsurface drip irrigation, in a semiarid area of central Tunisia. After assessing the validity of FAO-56 spreadsheet program to well simulate soil water status in the root zone, water use efficiency (WUE) was evaluated based on crop yield and simulated actual evapotranspiration. At the same time, irrigation water use efficiency (IWUE) was determined as the ration between crop yield and the amount of water supply to the crop (irrigation). Field experiments, were carried out in Central Tunisia (10 ° 33' 47.0" E, 35 ° 58' 8.1 ° N, 19 m a.s.l) on a potatoes crop planted in a sandy loam soil, during the growing season 2014, from 15 January to 6 May. Soil water status was monitored in two plots (T1 and T2) maintained under the same management, except for irrigation volumes, provided by a SDI system. More particular, irrigation was scheduled according to the average water content measured in the root zone, with a total of 8 watering, with timing ranging between one and three hours in T1, and between about half-an-hour and one-hour and a-half, in T2. FAO-56 was validated according the average soil water content in all tubes and all observation depths with RMSE values, equal to 0.012 cm3cm⁻³ and 0.028 cm3cm-3, respectively for T1 and T2. Simulated actual evapotranspiration in T1 was equal to the potential evapotranspiration. However, it resulted lower than potential evapotranspiration. WUE resulted equal to 32 Kg/m³ and 16 Kg/m³, whereas IWUE was equal to 31.7 Kg/m³ and 45.70 Kg/m³ for treatments T1 and T2. In terms of gross margin, T1 were more efficient than T2. This finding is directly related to sheep price of water, although its scarcity. The experimental results and model simulations provided useful guidelines for a more sustainable use of irrigation water.
... EVs are highly resistant in several environments and able to preserve their infectivity for months (Wetz et al., 2004;Fong and Lipp, 2005;Rajtar et al., 2008), which reflects their widespread occurrence in populations (Sellwood et al., 1981;Hovi et al., 1996;Sedmark et al., 2003). As other enteric viruses, they can contaminate soil, food crops and natural watercourses through the discharge of contaminated wastewater. ...
Chapter
Water scarcity is among the main problems to be faced by many societies on the World in the XXIst century. It is due the combination between the increase of urban and industrial needs and the effects of climate change. The approach to estimate climate change impacts on water resources consist on union between climate model outputs and hydrological models. However, due to the coarse resolution of Global Circulation Models (GCM), their outputs should been downscaled to match the scale of interest for an impact study. In literature, two downscaling methods have been showed. The first approach is Dynamical Downscaling (DD) and the second is Statistical Downscaling (SD) approach. Until now, the impacts of climate change on evapotranspiration have not been conclusively determined. Generally decrease in rainfall and increase in temperature will result in increase in evapotranspiration. In this context, the sustainable management of water resources requires a good control of the hydrological terms. Evapotranspiration, as the major component of water cycle, is the main way for water consumption of earth system. The accurate estimation of evapotranspiration has a great importance in hydrological modeling, irrigation planning and water resources management. In the Mediterranean regions, especially in Tunisia, the main climate is characterized by an important evaporation potential. This particularity is due to the conjugation between different climatic parameters. In Tunisia, irrigated agriculture uses about 83% of the total water resources. Thus, estimating evapotranspiration is the most important step for calculating crop water requirements that has a special economic importance in rationalization of water consumption in the agricultural field. Physically-based and empirical methods to estimate evapotranspiration are evaluated in different climatic environment under current climate conditions but also under recent, and in a changing climate.
... EVs are highly resistant in several environments and able to preserve their infectivity for months (Wetz et al., 2004;Fong and Lipp, 2005;Rajtar et al., 2008), which reflects their widespread occurrence in populations (Sellwood et al., 1981;Hovi et al., 1996;Sedmark et al., 2003). As other enteric viruses, they can contaminate soil, food crops and natural watercourses through the discharge of contaminated wastewater. ...
Chapter
Location of Tunisia between the Mediterranean and the Sahara, is an arid country on the major part of its territory. This aridity combined with variability Mediterranean climate makes water a resource both scarce and unevenly distributed in time and space. Tunisia is ranked by international organizations (World Bank, FAO, UNESCO) as being among the least endowed with groundwater resources countries in the Mediterranean basin. Salinity is a major environmental factor limiting plant growth and productivity. In arid and semi-arid regions of the world salinization is exacerbated by the development of soil sodicity, especially those regions with limited rainfall, high evapotranspiration, and high temperature. Sodicity is associated with the use of irrigation water containing high concentrations of sodium. Soil and water salinity in the arid regions are continuously increasing. The present contribution concerns the state of water resources in Tunisia, their management and the necessary services for an efficient water use. The physical major constraints are specified, for better irrigation practices in the field, water management modes, in particular with regards to water users associations.
... EVs are highly resistant in several environments and able to preserve their infectivity for months (Wetz et al., 2004;Fong and Lipp, 2005;Rajtar et al., 2008), which reflects their widespread occurrence in populations (Sellwood et al., 1981;Hovi et al., 1996;Sedmark et al., 2003). As other enteric viruses, they can contaminate soil, food crops and natural watercourses through the discharge of contaminated wastewater. ...
Chapter
In this study, AquaCrop model was evaluated for maize (Zea mays L.) in the experimental site of Chott Mariem, Sousse (semi-arid climate), with data from two companions corn grown in the years 2008 and 2010. The crop was led under subsurface drip irrigation (SDI) to 20 cm deep. The simulation was repeatedly made on three parameters to know soil water content (SWC), canopy cover and root development. The best wedging SWC belonged to statistical estimators values ranging from 1.1 to 3.34 for the RMSE, between [0-1] for R2 and efficiency EF (often positive) values very close to zero for the CRM (-0.001 for the water content to 20 cm depth), and a1 CD. Concerning the canopy cover calibration, the wedging settled with R2 in the range of 0.92 seen fit enough (the ideal is R2 = 1), and root development was rigged with a RMSE in the range of 3.13, an R2 = 0.92, a CRM, CD and EF in the desired standards. Although the quality of the calibration for all three parameters was considered good enough through graphics and estimators calculated, validation, concerning only the water content and root development, gave a perfect complement to only the root growth (R2 = 0.99). The validation of the moisture content with data of the partner 2008, indeed gave negative values of the efficiency EF in the majority of the depths, so showing that the experimental values are better than those feigned. This regression of the quality of validation was, according to us, the result of the various defects of the model to know the not consideration of the depth of the subsurface drip irrigation system, the conservatives parameters are not precise for a specific range and the fixation of the own percentages in sand, silt and clay by the user, is not possible.
... Because of the difficulty and expense associated with the direct detection of pathogens, fecal coliform bacteria are widely used as indicator organisms to signal the possible presence of feces and pathogenic organisms. While bacterial indicators have proven useful in helping to assess the sanitary condition of shellfish growing areas, there is growing recognition that they do not reliably predict the occurrence and survival of enteric viruses and other pathogens in the marine environment (Bosch 1998;Goyal et al. 1984;Hernroth et al. 2002;Jiang et al. 2001;Lees 2000;Lilja and Glasoe 1993;Lipp and Rose 1997;NRC 1993NRC , 1999NRC , 2004Noble et al. 2003a;Noble and Furmen 2001;Schroeder et al. 2002;USEPA 2001c;Wetz et al. 2004;Vasconcelos 2001). Other factors further complicate the indicator system and the task of accurately gauging growing-area conditions and related health risks. ...
... Regarding the physicochemical characteristics of the water samples, the salinity can also have a bias on the virus survival. Wetz et al. (2004) determined that the infectivity of poliovirus was affected by the salinity being rapidly reduced in unfiltered seawater under 22 and 30°C. On the other hand, Hurst and Gerba (1980) evalu- ating the stability of RV SA11 and other enteroviruses in estuarine waters from different sources and polluted and unpolluted freshwaters at 20°C, demonstrated high viral titre reductions in the estuarine water in comparison with freshwaters. ...
Article
Aims: To evaluate the thermal and length of stability of the RV vaccine (RotaTeq) in the aquatic environment. Methods and results: Surface freshwater, brackish and drinking water were spiked with RV vaccine strain and stored at 22 and 4 °C. The virus infectivity and genome persistence were evaluated by plaque assay and RT-qPCR respectively, up to 180 days. Infectious RV vaccine particles showed to be less stable in the brackish water matrix than surface and drinking water either at 22 or 4 °C. The estimated T90 values obtained by the linear regression model were 18, 55 and 59 days respectively for brackish, surface and drinking water stored at 22 °C and 68, 154 and 240 days at 4 °C. As expected, the genome persistence showed to be less affected by length and temperature of storage in all the matrices evaluated. Conclusions: The evidence of high stability of the RV vaccine in water matrices reinforces the importance for surveillance of RV vaccines strains in the environment regarding the potential occurrence of unexpected infections and virus genomic reassortments. Significance and impact of study: The presence of reassortants and the shedding of the live attenuated vaccine strains after vaccination can compromise the vaccine safety by introducing new viral variants in the environment. This article is protected by copyright. All rights reserved.
... Potable water is typically monitored for fecal indicator organisms to assess whether it is free of sewage-derived microorganisms and pathogens. Monitoring coastal waters using indicator organisms alone, however, may not prove as efficient in detecting whether microbial pathogens are present in beach waters[3][4][5]. Pathogens may enter the water directly from humans and animals swimming and recreating on the beach and may not correlate with fecal indicator bacteria[6][7][8]. ...
Article
Full-text available
Large sample volumes are traditionally required for the analysis of waterborne pathogens. The need for large volumes greatly limits the number of samples that can be processed. The aims of this study were to compare extraction and detection procedures for quantifying protozoan parasites and viruses from small volumes of marine water. The intent was to evaluate a logistically simpler method of sample collection and processing that would facilitate direct pathogen measures as part of routine monitoring programs. Samples were collected simultaneously using a bilayer device with protozoa capture by size (top filter) and viruses capture by charge (bottom filter). Protozoan detection technologies utilized for recovery of Cryptosporidium spp. and Giardia spp. were qPCR and the more traditional immunomagnetic separation-IFA-microscopy, while virus (poliovirus) detection was based upon qPCR versus plaque assay. Filters were eluted using reagents consistent with the downstream detection technologies. Results showed higher mean recoveries using traditional detection methods over qPCR for Cryptosporidium (91% vs. 45%) and poliovirus (67% vs. 55%) whereas for Giardia the qPCR-based methods were characterized by higher mean recoveries (41% vs. 28%). Overall mean recoveries are considered high for all detection technologies. Results suggest that simultaneous filtration may be suitable for isolating different classes of pathogens from small marine water volumes. More research is needed to evaluate the suitability of this method for detecting pathogens at low ambient concentration levels.
... While evidence showing that sewage is an important disease reservoir is limited to one type of disease and its associated causal agent, the potential for discovery of more examples is considerable, given the sheer numbers of microbes and viruses present in the average human gut and consequently in the average sewage effluent (e.g., see Refs. [91][92][93]. ...
Article
Full-text available
Coral reefs are in decline worldwide, and land-derived sources of pollution, including sewage, are a major force driving that deterioration. This review presents evidence that sewage discharge occurs in waters surrounding at least 104 of 112 reef geographies. Studies often refer to sewage as a single stressor. However, we show that it is more accurately characterized as a multiple stressor. Many of the individual agents found within sewage, specifically freshwater, inorganic nutrients, pathogens, endocrine disrupters, suspended solids, sediments, and heavy metals, can severely impair coral growth and/or reproduction. These components of sewage may interact with each other to create as-yet poorly understood synergisms (e.g., nutrients facilitate pathogen growth), and escalate impacts of other, non-sewage-based stressors. Surprisingly few published studies have examined impacts of sewage in the field, but those that have suggest negative effects on coral reefs. Because sewage discharge proximal to sensitive coral reefs is widespread across the tropics, it is imperative for coral reef-focused institutions to increase investment in threat-abatement strategies for mitigating sewage pollution. © 2015 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.
... Hepatitis A and E viruses are associated with poor countries that lack sanitation and strict hygiene controls. Viral pathogens that are associated with fecal contaminants tend to persist longer in the environment than do bacterial contaminants and are known for their ability to survive harsh weather and disinfecting treatments [29]. Adenovirus is an example of resilient virus that survives ultraviolet (UV) disinfection better than bacterial indicators [30]. ...
Article
Full-text available
The effect of human activities on water resources has expanded dramatically during the past few decades, leading to the spread of waterborne microbial pathogens. The total global health impact of human infectious diseases associated with pathogenic microorganisms from land-based wastewater pollution was estimated to be approximately three million disability-adjusted life years (DALY), with an estimated economic loss of nearly 12 billion US dollars per year. Although clean water is essential for healthy living, it is not equally granted to all humans. Indeed, people who live in developing countries are challenged every day by an inadequate supply of clean water. Polluted water can lead to health crises that in turn spread waterborne pathogens. Taking measures to assess the water quality can prevent these potential risks. Thus, a pressing need has emerged in developing countries for comprehensive and accurate assessments of water quality. This review presents current and emerging advanced techniques for assessing water quality that can be adopted by authorities in developing countries.
... Lipp et al. (2001a) detected the enterovirus in estuary water in Florida only at temperatures below 23°C. Wetz et al. (2004) showed that poliovirus is stable in water for 60 days at 22°C and 30 days at 30°C. Similarly, Gantzer et al. (1998) demonstrated to be necessary 671 days to inactivate 90% of poliovirus and HAV in water samples kept at 4°C and only 25 days at 25°C. ...
Conference Paper
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A nested-PCR method was used to detect the occurrence of human adenovirus in coastal waters of Southern California. Twenty- to forty-liter water samples were collected from 12 beach locations from Malibu to the border of Mexico between February and March 1999. All sampling sites were located at mouths of major rivers and creeks. Two ultrafiltration concentration methods, tangential flow filtration (TFF) and vortex flow filtration (VFF), were compared using six environmental samples. Human adenoviruses were detected in 4 of the 12 samples tested after nucleic acid extraction of VFF concentrates. The most probable number of adenoviral genomes ranged from 880 to 7,500 per liter of water. Coliphages were detected at all sites, with the concentration varying from 5.3 to 3332 PFU/liter of water. F-specific coliphages were found at 5 of the 12 sites, with the concentration ranging from 5.5 to 300 PFU/liter. The presence of human adenovirus was not significantly correlated with the concentration of coliphage (r = 0.32) but was significantly correlated (r = 0.99) with F-specific coliphage. The bacterial indicators (total coliforms, fecal coliforms, and enterococci) were found to exceed California recreational water quality daily limits at 5 of the 12 sites. However, this excess of bacterial indicators did not correlate with the presence of human adenoviruses in coastal waters. The results of this study call for both a reevaluation of our current recreational water quality standards to reflect the viral quality of recreational waters and monitoring of recreational waters for human viruses on a regular basis.
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The results of several studies conducted along the upper Texas Gulf coast, where a substantial amount of quantitative virological data were collected, are compared to bacteriological indicators and other environmental factors on a statistical basis. Variables common to all these studies were anlayzed by multivariate regression. Although multivariate analysis indicated that the number of viruses detected in water was related to rainfall, salinity, and total coliforms in the water, the amount of variation in the number of viruses accounted for by these factors was not large enough to make them good predictors. Enteroviruses were detected 43 per cent of the time in recreational waters considered acceptable as judged by coliform standards, and 44 per cent of the time when judged by fecal coliform standards. Enteroviruses were detected 35 per cent of the time in waters which met acceptable standards for shellfish-harvesting. Our failure to correlate the occurrence of enteroviruses in marine waters with indicator bacteria, and the frequent occurrence of enteroviruses in water which met current bacteriological standards, indicates that these standards do not reflect the occurrence of enteroviruses, and perhaps other human pathogenic viruses, in marine waters.
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Sewage waste disposal facilities in the Florida Keys include septic tanks and individual package plants in place of municipal collection facilities in most locations. In Key Largo, both facilities discharge into the extremely porous Key Largo limestone. To determine whether there was potential contamination of the subsurface aquifer and nearby coastal surface waters by such waste disposal practices, we examined the presence of microbial indicators commonly found in sewage (fecal coliforms, Clostridium perfringens, and enterococci) and aquatic microbial parameters (viral direct counts, bacterial direct counts, chlorophyll a, and marine vibriophage) in injection well effluent, monitoring wells that followed a transect from onshore to offshore, and surface waters above these wells in two separate locations in Key Largo in August 1993 and March 1994. Effluent and waters from onshore shallow monitoring wells (1.8- to 3.7-m depth) contained two or all three of the fecal indicators in all three samples taken, whereas deeper wells (10.7- to 12.2-m depth) at these same sites contained few or none. The presence of fecal indicators was found in two of five nearshore wells (i.e., those that were < or = 1.8 miles [< or = 2.9 km] from shore), whereas offshore wells (> or = 2.1 to 5.7 miles [< or = 3.4 to 9.2 km] from shore) showed little sign of contamination. Indicators were also found in surface waters in a canal in Key Largo and in offshore surface waters in March but not in August. Collectively, these results suggest that fecal contamination of the shallow onshore aquifer, parts of the nearshore aquifer, and certain surface waters has occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
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It is important to determine the stability of naked viral RNA in seawater, since false-positive results can occur when reverse transcriptase-PCR (RT-PCR) is used to detect viruses if the RT-PCR amplifies free RNA instead of RNA from intact viruses. An acid guanidinium thiocyanate-phenol-chloroform method was used to extract total RNA from a filtered poliovirus cell culture suspension. The sensitivity of detection in this viral RNA study was 600 fg when RT-PCR was used. The extracted total RNA was seeded into filtered and unfiltered seawater, and the resulting preparations were incubated at 4 degrees C and at room temperature (23 +/- 1 degrees C). Our results showed that the seeded RNA was more stable in filtered seawater than in unfiltered seawater at both temperatures. The viral RNA could not be detected by the RT-PCR after 2 days of incubation in unfiltered seawater and after 28 days of incubation in filter-sterilized seawater. Therefore, because of the relatively short life of viral RNA in natural water, the detection of virus in environmental samples by the RT-PCR was mainly due to the presence of well-protected viral particles and not due to the presence of naked viral RNA.
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Corals and reef environments are under increased stress from anthropogenic activities, particularly those in the vicinity of heavily populated areas such as the Florida Keys. The potential adverse impacts of wastewater can affect both the environment and human health; however, because of the high decay rate of bacterial indicators in coral reef waters it has been difficult to document the presence of microbial contaminants and to assign risks in these environments. Here we show initial evidence that microorganisms associated with human feces are concentrated along the surface of coral heads relative to the overlying water column in the Florida Keys. Bacterial indicators (fecal coliform bacteria, enterococci or Clostridium perfringens) were detected in 66.7% of the coral surface microlayer (CSM) samples at levels between five and 1000 CFU/100 ml, but were found infrequently and at low numbers in the overlying water column ( < or = 2.5 CFU/100 ml). Similarly, enterovirus nucleic acid sequences, an indicator of human-specific waste, were detected in 93.3% of the CSM samples and only once in the water column by cell culture. Results show that coral mucus may accumulate enteric microorganisms in reef environments, and may indicate a risk to public and environmental health despite low indicator levels in the surrounding water.
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Loss rates and loss processes for viruses in coastal seawater from the Gulf of Mexico were estimated with three different marine bacteriophages. Decay rates in the absence of sunlight ranged from 0.009 to 0.028 h ⁻¹ , with different viruses decaying at different rates. In part, decay was attributed to adsorption by heat-labile particles, since viruses did not decay or decayed very slowly in seawater filtered through a 0.2-μm-pore-size filter (0.2-μm-filtered seawater) and in autoclaved or ultracentrifuged seawater but continued to decay in cyanide-treated seawater. Cyanide did cause decay rates to decrease, however, indicating that biological processes were also involved. The observations that decay rates were often greatly reduced in 0.8- or 1.0-μm-filtered seawater, whereas bacterial numbers were not, suggested that most bacteria were not responsible for the decay. Decay rates were also reduced in 3-μm-filtered or cycloheximide-treated seawater but not in 8-μm-filtered seawater, implying that flagellates consumed viruses. Viruses added to flagellate cultures decayed at 0.15 h ⁻¹ , corresponding to 3.3 viruses ingested flagellate ⁻¹ h ⁻¹ . Infectivity was very sensitive to solar radiation and, in full sunlight, decay rates were 0.4 to 0.8 h ⁻¹ . Even when UV-B radiation was blocked, rates were as high as 0.17 h ⁻¹ . Calculations suggest that in clear oceanic waters exposed to full sunlight, most of the virus decay, averaged over a depth of 200 m, would be attributable to solar radiation. When decay rates were averaged over 24 h for a 10-m coastal water column, loss rates of infectivity attributable to sunlight were similar to those resulting from all other processes combined. Consequently, there should be a strong diel signal in the concentration of infectious viruses. In addition, since sunlight destroys infectivity more quickly than virus particles, a large proportion of the viruses in seawater is probably not infective. Images
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Domestic wastewater disposal practices in the Florida Keys are primarily limited to on-site disposal systems such as septic tanks, injection wells, and illegal cesspits. Poorly treated sewage is thus released into the highly porous subsurface Key Largo limestone matrix. To investigate the fate and transport of sewage in the subsurface environment and the potential for contamination of marine surface waters, we employed bacteriophages as tracers in a domestic septic system and a simulated injection well in Key Largo, Florida. Transport of bacteriophage (Phi)HSIC-1 from the septic tank to adjacent surface canal waters and outstanding marine waters occurred in as little as 11 and 23 h, respectively. Transport of the Salmonella phage PRD1 from the simulated injection well to a canal adjacent to the injection site occurred in 11.2 h. Estimated rates of migration of viral tracers ranged from 0.57 to 24.2 m/h, over 500-fold greater than flow rates measured previously by subsurface flow meters in similar environments. These results suggest that current on-site disposal practices can lead to contamination of the subsurface and surface marine waters in the Keys.
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Recent evidence suggests that viruses play an influential role within the marine microbial food web. To understand this role, it is important to determine rates and mechanisms of virus removal and degradation. We used plaque assays to examine the decay of infectivity in lab-grown viruses seeded into natural seawater. The rates of loss of infectivity of native viruses from Santa Monica Bay and of nonnative viruses from the North Sea in the coastal seawater of Santa Monica Bay were determined. Viruses were seeded into fresh seawater that had been pretreated in various ways: filtration with a 0.2-(mu)m-pore-size filter to remove organisms, heat to denature enzymes, and dissolved organic matter enrichment to reconstitute enzyme activity. Seawater samples were then incubated in full sunlight, in the dark, or under glass to allow partitioning of causative agents of virus decay. Solar radiation always resulted in increased rates of loss of virus infectivity. Virus isolates which are native to Santa Monica Bay consistently degraded more slowly in full sunlight in untreated seawater (decay ranged from 4.1 to 7.2% h(sup-1)) than nonnative marine bacteriophages which were isolated from the North Sea (decay ranged from 6.6 to 11.1% h(sup-1)). All phages demonstrated susceptibility to degradation by heat-labile substances, as heat treatment reduced the decay rates to about 0.5 to 2.0% h(sup-1) in the dark. Filtration reduced decay rates by various amounts, averaging 20%. Heat-labile, high-molecular-weight dissolved material (>30 kDa, probably enzymes) appeared responsible for about 1/5 of the maximal decay. Solar radiation was responsible for about 1/3 to 2/3 of the maximal decay of nonnative viruses and about 1/4 to 1/3 of that of the native viruses, suggesting evolutionary adaptation to local light levels. Our results suggest that sunlight is an important contributing factor to virus decay but also point to the significance of particles and dissolved substances in seawater.
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Water is a common vehicle for the transmission of many enteric viruses. Enteric viruses survive longer in fresh and marine water than coliform bacteria, which are used to monitor water quality. In marine and other surface waters, numbers of enteric viruses are often too low to be detected in unconcentrated samples. Therefore, large volumes of water must be concentrated by adsorption/filtration and elution (desorption) before analysis. More than 100 types of human pathogenic viruses are present in fecally contaminated water, and are detected by the current available methods. The detection of adenoviruses, hepatitis A virus, astroviruses, and rotaviruses by cell culture is possible; however, the methods are tedious and less often used. Nucleic acid hybridization and the polymerase chain reaction (PCR) are used for detecting human viruses and other fastidious microbial pathogens in the environment. Molecular detection methods are important in studying the occurrence of Hepatitis A and Norwalk-like viruses, which are epidemiologically important pathogens but do not produce cytopathogenic effects (CPE) readily in cell culture. Molecular techniques have also enhanced the speed and sensitivity of detection for the more routinely cultured enteroviruses.
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To understand the roles of marine viruses in marine microbial food webs, it is important to determine rates and mechanisms of virus degradation and subsequent uptake of degraded virus material and other cell lysis products by heterotrophic marine bacteria. We radiolabeled and concentrated viruses and viral lysis products from either pure cultures ((3)H) Or natural communities ((3)H and (33)P) and added them to seawater samples of differing trophic status from coastal (mesotrophic) and offshore (oligotrophic) California waters and French Mediterranean waters (oligotrophic). Rates of degradation were determined by the loss of high molecular weight radiolabel over time and the fate of the degraded material (microbial uptake or accumulation in low molecular weight pools) was followed by size fractionation and/or acid extraction. Preliminary experiments with (3)H-labeled, single-stranded RNA phage MS2 and marine phage H11/1 demonstrated that MS2 degraded significantly faster in coastal Santa Monica Bay seawater (2.5 +/- 0.6% h(-1)), than the marine phage, H11/1 (0.99 +/- 0.1% h(-1)). For labeled virus material from natural populations, rates of degradation were slower in oligotrophic waters (ranges from 1.0 to 3.3% h(-1)) than in mesotrophic waters (ranges from 4.9 to 6.0% h(-1)), corresponding to turnover rates of 1 to 4 d for this material. Degradation rates of labeled virus material are likely underestimates, because during preparation, degradation and uptake are continually occurring, resulting in accumulation of the less reactive products. The proportion of radiolabeled material taken up by microbes was greatest in oligotrophic waters, especially in the phosphate-limited Villefranche Bay, France, where most of the (33)PO(4)-labeled material was taken up in less than 7 h. In contrast, the majority of degraded 3H-labeled material was not accumulated into biomass, and in 3 of 4 samples, accumulation was hardly detectable. The results suggest that viruses and lysis products are labile and turn over relatively rapidly, but often may not be efficiently incorporated into bacterial biomass.
Article
The failure of a large percentage of previously monodispersed virus added to artificial seawater to pass through membrane filters which would exclude the passage of aggregates indicated that extensive aggregation was taking place in artificial seawater. The loss of viral titer in artificial seawater was found to be directly related to salinity as was the extent of aggregation. Aggregation also appeared to be taking place in natural seawater, but was not as extensive. Viral clumps formed in both natural and artificial seawater could be disaggregated by an increase in the amount of organic matter or a decrease in salinity. Aggregation may play a role in the initial decline of viral titer in seawater, as well as to reduce the number of “infectious foci” present in seawater.
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Microbiological water quality at beaches is typically measured only by indicator bacteria, even though viruses are also a concern, because classical culture-based virus assays are not suitable. In this study, molecular-based assays for the detection of enteroviruses by reverse transcriptase polymerase chain reaction (RT-PCR) were performed on 50 coastal seawater samples taken from Santa Monica Bay, CA, over a six-year period, and compared with indicator bacteria. Sample sites were near freshwater outlets in the Bay and popular sandy beaches. RT-PCR is a primer-based molecular biology technique, used to detect the genomes of specific groups or types of viruses based upon conserved sequences. Results of the 50 analyses showed our ultrafiltration concentration methods and RT-PCR protocol could be used consistently to detect enteroviruses from 20 l samples of coastal seawater. Of the 50 samples, 16 (32%) were positive for enteroviruses, 27 (54%) were negative and 7 (14%) were inconclusive. There was no significant correlation between the presence of enteroviruses and individual standard microbiological indicators of fecal contamination, specifically total coliforms, fecal coliforms, or enterococci (r=0.14, r=0.28 and r=0.34, respectively, p>0.05). However, there was a significant correlation (r=0.71) to a combined set of bacterial water quality standards, involving all three indicators, recently adopted in California. There was no significant correlation between the RT-PCR results and levels of rainfall (a large source of runoff), but our analyses demonstrated that positive results for enteroviruses were significantly more likely during the winter `wet' season than during the summer `dry' season. Our results demonstrate that RT-PCR is an effective method for the detection of enteroviruses in coastal seawater, and they suggest that bacterial indicators are not necessarily good predictors of the presence of such viruses. Enteroviruses are known to be important etiological agents of disease from recreational water contact, so analysis for their presence might be advisable at certain locations (e.g. high-use sandy beaches) or during certain seasons of the year.
Article
The Charlotte Harbor estuary in southwest Florida was sampled monthly for one year at twelve stations, in the lower reaches of the Myakka and Peace Rivers. The objectives of the study were to address the distribution and seasonal changes in microbial indicators and human pathogen levels in Charlotte Harbor shellfish and recreational waters, and to determine those factors that may be important in the transport and survival of pathogens. Monthly water samples and quarterly sediment samples were analyzed for fecal coliform bacteria, enterococci,Clostridium perfringens, and coliphage. Quarterly samples also were analyzed for the enteric human pathogens,Cryptosporidium spp.,Giardia spp., and enteroviruses. Fecal indicator organisms were generally concentrated in areas of low salinity and high densities of septic systems; however, pollution became widespread during wet weather in, the late fall and winter of 1997–1998, coincident with a strong El Nino event. Between, December 1997 and February 1998, enteroviruses were detected at 75% of the sampling stations; none were detected in other months. Enteric protozoa were detected infrequently and were not related to seasonal influences. Fecal indicators and enteroviruses were each significantly associated with rainfall, streamflow, and temperature. Regression models suggest that temperature and rainfall can predict the occurrence of enteroviruses in 93.7% of the cases. Based on findings in this watershed, factors such as variability in precipitation, streamflow, and temperature show promise in modeling and forecasting periods of poor coastal water quality.
Article
One of the methods for domestic wastewater disposal in the Florida Keys is injection of partially treated wastewater into the highly porous limestone bedrock using waste disposal or injection wells. In an effort to understand the transport and fate of wastewater, we utilized bacteriophages as tracers in a 12.2-m deep, simulated injection well in Key Largo and an active (27.4 m deep) class V disposal well in the Middle Keys. The latter is the currently permitted type of injection well used for multi-unit domestic waste disposal in the Keys. Surface waters and groundwater at several sites were monitored for 5 days after seeding of the injection wells. In both environments, viral tracers appeared after short periods of time in groundwater (8 h after injection) and surface marine waters (10 h and 53 h for Key Largo and the Middle Keys, respectively). Estimated rates of tracer movement were greatest in Key Largo (2.5–35 m/h), where tidal pumping was implicated in tracer movement. In the Middle Keys, the pattern of movement showed little evidence of tidal pumping, and migration rates were slower (0.12–2 m/h). Collectively these results indicate that wastewater injected into the subsurface can make its way rapidly to surface marine waters, where it may contribute to water quality deterioration.
Article
Nucleic acid hybridization has been used to detect viral nucleic acid in water. This type of assay, in contrast with tissue culture assays, may not distinguish between viable and non-viable viruses. We evaluated, by comparison with tissue culture infectivity assay (plaque forming method), the ability of the gene probe assay to detect viable poliovirus 1 (LSc) in well water, autoclaved well water, filter-sterilized well water and autoclaved phosphate buffered saline kept at 37 and 15°C for 75 days, and in dechlorinated tap water held at room temperature. A gradual decline in numbers of poliovirus was observed in all of the samples by cell culture assay. With the exception of autoclaved well water and phosphate buffer, a parallel decline in virus detectable by gene probe occurred in all other water samples. These results suggest that detection of poliovirus 1, by gene probe, is influenced by the presence of microorganisms or their products and to a lesser extent by temperature. This suggests that in some natural waters, the detection of poliovirus 1, by gene probe, may be expected to correlate to detection by tissue culture.
Article
Survival of poliovirus 1 was determined in sterile seawater at different salinity levels by detection of viral RNA by RT-PCR and comparison with tissue culture infectivity assay. Salinity appeared to have little influence on the behaviour of infectious particles: times necessary to obtain negative results by cell culture were not statistically different for the three salinities tested. Viral RNA was always detected by RT-PCR showing that in sterile medium viral particles can persist in a noninfectious form.
Article
The hepatitis A virus (HAV) and poliovirus 1 were added to estuarine water samples and their stability in maintenance medium was compared to that in water samples untreated and treated by heat and filtration. The inactivation curves show that the inactivating factor is biological in nature.
Article
To improve the knowledge of the survival of enteric viruses in a marine environment, the influence of physico-chemical parameters (temperature, UV, salinity) on the survival of infectious poliovirus 1 and hepatitis A virus (HAV) in seawater was first studied, the influence of suspended solids (SS) on poliovirus adsorption and survival in seawater was then evaluated and the detection of rotavirus genome in environmental samples (shellfish, river water, treated wastewater) was finally investigated. The results show that temperature has a major impact on virus survival in seawater as the time necessary to inactivate 90 % of the virus (T90) is 671 days at 4 °C and only 25 days at 25 °C. Ultraviolet light (42 mW s cm−2) rapidly inactivates viruses but HAV is more resistant (T90 = 2.6 min) than the poliovirus 1 (T90 = 1.3 min). By contrast, seawater salinity has no effect on virus survival. In presence of SS, 90 % to 99.9 % of the viruses were adsorbed. This adsorption does not provide any protection for viruses with low SS concentrations (3 and 15 mg L−1) but a slight increase in virus survival was observed with a high SS concentration (500 mg L−1). Finally environmental sample analysis indicated that 20 % shellfish, about 40 % river water and 40 % treated wastewater tested positive for the rotavirus genome.
Article
Methods are described for the efficient concentration of an enterovirus from large volumes of tap water, sewage, and seawater. Virus in acidified water (pH 3.5) in the presence of aluminum chloride was adsorbed to a 10-inch (ca. 25.4 cm) fiberglass depth cartridge and a 10-inch pleated epoxy-fiberglass filter in a series at flow rates of up to 37.8 liters (10 gallons) per min. Adsorbed viruses were eluted from the filters with glycine buffer (pH 10.5 to 11.5), and the eluate was reconcentrated by using a combination of aluminum flocculation followed by hydroextraction. With this procedure, poliovirus in large volumes of tap water, seawater, and sewage could be concentrated with an average efficiency of 52, 53, and 50%, respectively. It was demonstrated that this method is capable of detecting surface solid-associated viruses originating from sewage treatment plants. No difference in virus recovery between laboratory batch studies and a set-up with acid-salt injection was found. This unified scheme for the concentration of viruses has many advantages over previously described systems. These include: high operating flow rates, low weight and small size, effectiveness with a variety of waters with widely varying qualities, and filters with a high resistance to clogging.
Article
A membrane filter procedure has been developed for the rapid quantitation of C. perfringens in the aquatic environment. Background growth is inhibited by the use of D-cycloserine, polymyxin B sulfate, and incubation at 45 degrees C. Differential characteristics include the fermentation of sucrose, production of acid phosphatase, and the absence of beta-D-glucosidase activity. The medium is prepared as follows (in grams per 100 ml of distilled water): tryptose, 3.0; yeast extract, 2.0; sucrose, 0.5; L-cysteine, 0.1; MgSO4. 7H2O, 0.01; bromocresol purple, 0.004; and agar, 1.5. The ingredients are dissolved, and the pH is adjusted to 7.6. After autoclaving at 121 degrees C for 15 min, the medium is allowed to cool at 50 degrees C, and the following are added per 100 ml: D-cycloserine, 40 mg; polymyxin B sulfate, 2.5 mg; indoxyl-beta-D-glucoside, 60 mg; 2.0 ml of a filter-sterilized 0.5% phenolpthalein diphosphate solution; and 0.2 ml of a filter-sterilized 4.5% FeCl3.6H2O solution. Enumeration of C. perfringens in a water sample is completed within 18 to 24 h. The verification of typical colonies was 93%. The average recovery from peptone-water spore suspensions of five strains was 79%, and that from filter-sterilized seawater suspensions was 90%. The precision of the method was approximately equal to that expected from random error alone. Confirmed recoveries of C. perfringens from water and sewage samples generally were greater than those by the Bonde pour tube method.
Article
The survival of indigenous enteric viruses in samples of unconcentrated and concentrated waste water sludge eluates, which had been prepared using a combination beef extract elution - organic flocculation concentration procedure, was studied at 2, 23, and -70 degrees C. Changes of virus titer occurring in the samples were followed during an 84-day observation period, with rates of change then calculated by least-squares regression. Virus survival in both types of eluates was statistically dependent (p less than or equal to 0.05) upon storage temperature. Based upon the observed rates of inactivation the average times which would be required for a 90% decrease (one log10 unit) in virus titer for unconcentrated eluates are 27 days at 23 degrees C, 198 days at 2 degrees C, and 375 days at -70 degrees C. The calculated average times required for a 90% decrease in virus titer for concentrated eluates are 22 days at 23 degrees C, 132 days at 2 degrees C, and 246 days at -70 degrees C. In both types of eluates the rates of virus inactivation at 2 degrees C were statistically different from those observed at 23 degrees C, but not different from those observed at -70 degrees C. The three study temperatures were selected to approximate holding of samples in an air-conditioned room, fluid on wet ice (H2O), and frozen on dry ice (CO2).
Article
The goals of this study were to assess watersheds impacted by high densities of OSDS (onsite sewage disposal systems) for evidence of fecal contamination and evaluate the occurrence of human pathogens in coastal waters off west Florida. Eleven stations (representing six watersheds) were intensively sampled for microbial indicators of fecal pollution (fecal coliform bacteria, enterococci, Clostridium perfringens and coliphage) and the human enteric pathogens, Cryptosporidium, Giardia, and enteroviruses during the summer rainy season (May-September 1996). Levels of all indicators ranged between < 5 and > 4000 CFU/100 ml. Cryptosporidium and Giardia were detected infrequently (6.8% and 2.3% of samples tested positive, respectively). Conversely, infectious enteroviruses were detected at low levels in 5 of the 6 watersheds sampled. Using cluster analysis, sites were grouped into two categories, high and low risks, based on combined levels of indicators. These results suggest that stations of highest pollution risk were located within areas of high OSDS densities. Furthermore, data indicate a subsurface transport of contaminated water to surface waters. The high prevalence of enteroviruses throughout the study area suggests a chronic pollution problem and potential risk to recreational swimmers in and around Sarasota Bay.
Article
The survival of Escherichia coli, Salmonella typhi, Shigella sonnei, poliovirus type 1 and a parvovirus (Minute Virus of Mice) was determined in seawater. Seeded seawater was incubated in the laboratory at 6, 12, 20 and 28 degrees C for up to 40 d. In-situ survival studies were done seasonally (winter, spring, summer and fall) using seeded microbial dialysis equipment placed in the Atlantic Ocean off coastal North Carolina at water depths of 3-10 m. In laboratory studies all test microbes survived longer at lower temperatures with typical times for 90% inactivation (T90) of 1-3 d at the highest temperature and > 10 d at the lowest temperature. Of the microbes tested, E. coli survived least well while S. typhi and Sh. sonnei survived similar to or greater than enteric viruses. Parvovirus survival was similar to that of poliovirus. Under in-situ conditions, E. coli also survived least well of all microbes tested with T90 values of 0.9-3.9 d depending upon season. All other test microbes had generally similar survivals. Overall, microbial survival in seawater was greater under laboratory conditions than under in-situ conditions. There was no clear association between microbial survival and water temperature. The lower survival of E. coli compared to the bacterial and viral pathogens under laboratory conditions raises concerns because it is a key microbial indicator of faecal contamination.
Article
A method was developed for the quantitative detection of pathogenic human enteroviruses from surface waters in the Florida Keys using Taqman (R) one-step Reverse transcription (RT)-PCR with the Model 7700 ABI Prism (R) Sequence Detection System. Viruses were directly extracted from unconcentrated grab samples of seawater, from seawater concentrated by vortex flow filtration using a 100 kD filter and from sponge tissue. Total RNA was extracted from the samples, purified and concentrated using spin-column chromatography. A 192-196 base pair portion of the 5' untranscribed region was amplified from these extracts. Enterovirus concentrations were estimated using real-time RT-PCR technology. Nine of 15 sample sites or 60% were positive for the presence of pathogenic human enteroviruses. Considering only near-shore sites, 69% were positive with viral concentrations ranging from 9.3 viruses/ml to 83 viruses/g of sponge tissue (uncorrected for extraction efficiency). Certain amplicons were selected for cloning and sequencing for identification. Three strains of waterborne enteroviruses were identified as Coxsackievirus A9, Coxsackievirus A16, and Poliovirus Sabin type 1. Time and cost efficiency of this one-step real-time RT-PCR methodology makes this an ideal technique to detect, quantitate and identify pathogenic enteroviruses in recreational waters.
Article
Discharge of inadequately treated wastewater into streams may result in the dissemination of pathogens and the contamination of surface water sources. Determining the die-off rate of pathogenic microorganisms in stream and sea waters may serve as the basis for evaluating the health risks posed by the presence of pathogens in seawater. This study was conducted to determine the effect of microbial load, temperature, salinity and turbidity on the die-off of oocysts of Cryptosporidium as compared to that of coxsackie A9 virus (Cox A9) and E. coli. The test microorganisms were seeded into stream, outfall or sea waters and incubated at either 30 degrees C (summer) or 15 degrees C (winter). At 30 degrees C, the fastest die-off was observed for Cox A9 where < 5-log was reduced regardless of the water quality. At 1 degrees C Cox A9 persistence was similar to that of Cryptosporidium where no change was detected in the concentration of either throughout the study period. E. coli die-off reached 5 orders of magnitude within 10d then its concentration remained unchanged. The die-off of E. coli was faster than observed for Cox A9 at 15 degrees C regardless of the water quality. No decrease was observed in the viability of Cryptosporidium under all tested conditions throughout the study period indicating the unsuitability of E. coli to serve as an indicator for the presence of parasites and viruses in stream and marine waters. The prolonged persistence of pathogenic microorganisms in marine waters suggested that discharge of contamination into streams may present a serious environmental health risk.