Article

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

May 2004
Marine Pollution Bulletin 48(7-8):698-704

DOI:10.1016/j.marpolbul.2003.09.008

Source
PubMed

Authors:

Jennifer Jarrell Wetz

Texas A&M University - Corpus Christi

Dale W Griffin

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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).

DISTRIBUTION OF ENTERIC VIRUSES IN THE GULF OF TRIESTE AND THEIR INTERACTIONS WITH ENVIRONMENTAL AND BIOLOGICAL PARAMETERS DISSERTATION

Thesis

Full-text available

Jun 2018

José Gonçalves

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.

Water-Mediated Transmission of Plant, Animal, and Human Viruses

Chapter

Jan 2018
ADV VIRUS RES

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.

Human enteric pathogens circulation in the Bogotá region and its impact on the health of vulnerable communities

Thesis

Dec 2020

Jose Jordan lozano

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.

Environmental stability of porcine respiratory coronavirus in aquatic environments

Article

Jul 2021
PLOS ONE

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.

Phycotoxin-Enriched Sea Spray Aerosols: Methods, Mechanisms, and Human Exposure

Article

Apr 2021
ENVIRON SCI TECHNOL

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.

Detection of Enteric Viruses and Bacterial Indicators in a Sewage Treatment Center and Shallow Water Bay

Article

Full-text available

Sep 2020

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.

Relationships between Microbial Indicators and Pathogens in Recreational Water Settings

Article

Full-text available

Dec 2018
Int J Environ Res Publ Health

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.

Human and animal enteric viral markers for tracking the sources of faecal pollution

Chapter

Jan 2018

Polioviruses and other Enteroviruses

Chapter

Apr 2017

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.

Viruses as Indicators of Fecal Pollution in Aquatic Environment

Article

Full-text available

Oct 2022

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

Mega-scale desalination Efficacy (Reverse Osmosis, Electrodialysis, Membrane Distillation, MED, MSF) during COVID-19: Evidence from salinity, pretreatment methods, temperature of operation

Article

Full-text available

Dec 2022

Seyed Masoud Parsa

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.

Tracing Foodborne Pathogens Using Molecular-Based Approaches

Chapter

Dec 2022

Molecular Characterization of Foodborne Pathogens

Chapter

Aug 2022

Occurrence of enteric viruses and fecal indicators in submarine groundwater discharges in the coastal environment of the Mexican Caribbean

Article

Jul 2022

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.

Coral growth anomalies, neoplasms, and tumors in the Anthropocene

Article

Jun 2022
TRENDS MICROBIOL

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.

Decay of four enteric pathogens and implications to wastewater-based epidemiology: Effects of temperature and wastewater dilutions

Article

Nov 2021
SCI TOTAL ENVIRON

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.

Survival of human enteric and respiratory viruses on plastics in soil, freshwater, and marine environments

Article

May 2021
ENVIRON RES

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.

Uncertainties in estimating SARS-CoV-2 prevalence by wastewater-based epidemiology

Article

Feb 2021
CHEM ENG J

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.

Male-Specific and Somatic Coliphage Profiles from Major Aquaculture Areas in Republic of Korea

Article

Full-text available

Sep 2020

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.

Assessment of the stability of human viruses and coliphage in groundwater by PCR and infectivity methods.

Article

Full-text available

Jul 2009

Mark Laverick

Assessment of enteroviruses from sewage water and clinical samples during eradication phase of polio in North India

Article

Full-text available

Oct 2018
VIROL J

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.

Microcosm environment models for studying the stability of adenovirus and murine norovirus in water and sediment

Article

Apr 2018
INT J HYG ENVIR HEAL

Influence of Environmental Conditions on Norovirus Presence in Mussels Harvested in Montenegro

Article

Full-text available

Dec 2017

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.

Applications and perspectives on microfluidic technologies in ships and marine engineering: a review

Article

Full-text available

Feb 2017
MICROFLUID NANOFLUID

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

Combining FAO-56 with an Economic Model to Assess Deficit Irrigation of Moderate Sensible Crop for Water Stress under Semi Arid Climate

Chapter

Nov 2016

Boutheina Douh

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.

Climate Change Effects on Evapotranspiration Estimated by Different Empirical Models under Mediterranean Environment

Chapter

Nov 2016

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.

Irrigation and Soil Salinity in Tunisia

Chapter

Nov 2016

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.

Performance Evaluation of Aquacrop in Simulating Soil Water Content, Canopy Cover, and Root Development for Maize Conducted under Subsurface Drip Irrigation

Chapter

Nov 2016

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.

Literature Review and Analysis: Coastal Urbanization and Microbial Contamination of Shellfish Growing Areras

Technical Report

Full-text available

Jun 2004

Rotavirus vaccine stability in the aquatic environment

Article

Dec 2015
J APPL MICROBIOL

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.

Quantification of Protozoa and Viruses from Small Water Volumes

Article

Full-text available

Jun 2015
Int J Environ Res Publ Health

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.

Sewage pollution: mitigation is key for coral reef stewardship: Sewage pollution and coral reef stewardship

Article

Full-text available

May 2015
ANN NY ACAD SCI

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.

Article

Full-text available

Feb 2015

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.

Virus Reviews and Research WATERBORNE VIRAL PATHOGENS: DETECTION, CONTROL AND MONITORING OF WATER QUALITY FOR HUMAN CONSUMPTION INTRODUCTION

Conference Paper

Full-text available

Jun 2013

The viral contamination of water for human consumption is a common cause of diseases outbreaks, therefore, a matter of great relevance for public health, especially in developing countries. In most countries, legislation recommends the study of coliforms to indicate the potability of water, however, this is not correlated with the presence of virus. The present review sought to characterize the epidemiological importance of waterborne viral diseases and the limitations of laboratorial detection and elimination of these pathogens. Besides, the state of art of virus as a tool to assess the quality of the water, as well as, the use of a single virus as the indicator of environmental contamination by virus itself are presented. Reports have demonstrated that some viruses are resistant to conventional water treatment process. Changes in water treatment policy should be achieved, and, should involve viral detection and resistance to physical and chemical agents, amongst other methods. However, we have to bear in mind that the decrease of waterborne infectious diseases is greatly dependent upon the improvement of sanitation, water treatment, together with preventive measures. All those measures together could ensure appropriate conditions for the promotion of human health and the reduction of environmental impacts.

Detection of Six Different Human Enteric Viruses Contaminating Environmental Water in Chiang Mai, Thailand

Article

Dec 2022

Human enteric viruses are a major cause of gastrointestinal illness, and these viruses can be introduced into environmental water through various routes. Viral contamination in water could play a significant role in human health.

Analysis of the Environmental Quality of Seawater in the Bohai Sea, China

Article

Sep 2022

According to the survey data on seawater quality in the Bohai Sea from 2020 to 2021, a single-factor data analysis was carried out on the seawater environmental quality of Liaoning, Hebei, Tianjin, Shandong and the offshore waters. The results show that the seawater quality of the Bohai Sea in 2021 Compared with the more serious pollution in 2020, the main pollutants are active phosphate and inorganic nitrogen. The spatiotemporal distribution characteristics of the eutrophication state index are high at the top of Bohai Bay and low on the outside, high in the southeast and low in the northwest. And through the comparison of water quality data for two years, the organic pollution and eutrophication near Panjin, Dalian, Yingkou and Weifang are getting worse day by day and the content of inorganic nitrogen and active phosphate in some waters in the Bohai Bay has increased. The total amount of materials discharged into the sea is controlled.

Occurrence of Fibropapillomatosis in Green Turtles (Chelonia mydas) in Relation to Environmental Changes in Coastal Ecosystems in Texas and Florida: A Retrospective Study

Article

Full-text available

May 2022

Fibropapillomatosis is a neoplastic disease of marine turtles, with green turtles (Chelonia mydas) being the most affected species. Fibropapillomatosis causes debilitating tumor growths on soft tissues and internal organs, often with lethal consequences. Disease incidence has been increasing in the last few decades and the reason is still uncertain. The potential viral infectious agent of Fibropapillomatosis, chelonid herpesvirus 5, has been co-evolving with its sea turtle host for millions of years and no major mutation linked with increased disease occurrence has been detected. Hence, frequent outbreaks in recent decades are likely attributable to external drivers such as large-scale anthropogenic changes in the green turtle coastal marine ecosystem. This study found that variations in sea surface temperature, salinity, and nutrient effluent discharge from nearby rivers were correlated with an increased incidence of the disease, substantiating that these may be among the significant environmental drivers impacting Fibropapillomatosis prevalence. This study offers data and insight on the need to establish a baseline of environmental factors which may drive Fibropapillomatosis and its clinical exacerbation. We highlight the multifactorial nature of this disease and support the inclusion of interdisciplinary work in future Fibropapillomatosis research efforts.

Plant Responses to Sewage Pollution

Chapter

Oct 2020

Sewage is the term used for waste water that often contains faeces, urine and laundry waste. The volume of sewage in the world is increasing in leaps and bounds together with the increasing population of the world. So, sewage pollution has become a major problem throughout the world. But the situation is particularly acute in developing countries due to exponential growth of population, urbanization and lack of technical development in these countries. It is important to highlight that although Antarctica has no native human population, yet, unprocessed sewage effluents from various research stations have been reported to cause negative effects on local wildlife of terrestrial and aquatic habitats. Sewage sludge contains excess of nutrients (nitrates, phosphates, organic matter) and heavy metals, which cause eutrophication in water bodies with subsequent increase in algal biomass, primary production and decrease in dissolved oxygen. The over-populating algae and bacteria use up most of the dissolved oxygen of water, making it difficult for other aquatic organisms to live. There are positive as well as negative responses of plants to the sewage effluents. Research shows that low and moderate concentration of sewage irrigation causes stimulated seed germination and seedling growth together with an increase in pigments synthesis, carbohydrates and nucleic acids synthesis. On the contrary, studies reveal that high dose of heavy metal concentration for plants via sewage irrigation/sewage sludge-amended soil caused inauspicious alterations in physiological and biochemical characteristics of plants like a decline in biomass and yield. Furthermore, continuous sewage irrigation in cropland leads to uninterrupted supply of minerals and nutrients resulting in adverse effects on yield quality and biomass due to oxidative damage and risks of plants to counteract stress factors. The plant either becomes toxic to its consumer or it dies from the mineral toxicity. Many plant species provide remedies to the sewage pollution by phytoremediation and this is a cost-effective method for sewage treatment.

Viral uptake and stability in Crassostrea gigas oysters during depuration, storage and steaming

Article

Sep 2019

More stable than bacteria in environmental samples, enteric viruses are generally related to outbreaks of gastroenteritis caused by the consumption of contaminated oysters. This study evaluated: i) the dynamic processes of enteric viral models bioaccumulation by Crassostrea gigas oysters artificially contaminated; ii) the stability of these viruses in oysters in controlled temperature conditions and iii) the effect of UV light in inactivating these viruses in depurated oysters. Plaque assay (PA) was used to assess the infectivity of both viral models. Cell culture coupled with RT-qPCR (ICC-RT-qPCR) was used to measure infectious adenovirus type 2 (HAdV-2) genomes and qPCR to measure genome copies of murine norovirus (MNV-1). The virus uptake through bioaccumulation behave differently: HAdV-2 reached its peak of uptake faster than MNV-1. Both viruses showed high stability in oysters when maintained under 4 °C, but were completely inactivated in steamed oysters. The HAdV-2 was completely inactivated after 12 h of depuration with UV light and after 24 h without UV light. After 72 h of depuration, MNV-1 was still detected in both tanks, probably due to the stronger interaction of this virus with the oyster's tissues. This study demonstrated the importance of a secure depuration time in ensuring a clean and safe product, and that the steaming process is the safest way to prepare oysters for consumption.

Persistance des entérovirus dans les eaux usées à Yopougon, Côte d'Ivoire

Article

Full-text available

Jan 2011

Plusieurs facteurs environnementaux contribuent au maintien de l’infectivité des entérovirus hors de l’organisme dans divers milieux hydriques pendant parfois de longues périodes. Cette étude effectuée in situ avait pour but : (i) d’isoler les entérovirus des eaux usées urbaines et lagunaires sur quatre lignées cellulaires, (ii) de suivre la distribution et la persistance de ces virus sous l’influence des facteurs environnementaux abiotiques. Les échantillons d'eaux usées ont été collectés à neuf points de prélèvement le long d'un canal dont l'écoulement débouche sur une lagune tropicale à Yopougon. Les entérovirus ont été concentrés par l’utilisation de DextranT40 et du Polyéthylène glycol 6000 selon des recommandations de l'OMS. Les mesures du pH, de la température, de la conductivité et de la salinité ont été effectuées sur site. La détermination des sulfates (SO 4 ²⁻ ) a été réalisée conformément à la HACH METHOD 8051. Parmi les échantillons d'eaux usées brutes (n = 45) et lagunaire (n = 21), 68,9 % et 52,4 % respectivement se sont révélés positifs à l'isolement viral. La présence des entérovirus a été confirmée par RT-PCR dans 57,8 % et 42,8 % des échantillons d'eaux usées brutes et lagunaires. Nous avons observé pour des pluviométries de 0,4 mm et de 252,9 mm que des échantillons étaient positifs respectivement dans 44,4 % et 60,9 % des cas. Par ailleurs, les entérovirus infectieux ont été détectés en milieu lagunaire pour une gamme de températures oscillant de 26 o C à 30 o C. Ces valeurs se situent au-dessus du seuil de 22 o C où leur survie serait affectée dans les estuaires. Cette étude semble démontrer que la valeur maximale du pH (pH Max = 9,57) et de la salinité (salinité Max = 10,7) couplée à d'autres facteurs environnementaux ne favoriserait pas la persistance des entérovirus. Les interactions entre ces eaux et les populations le long du canal et en aval exposent celles-ci à des risques sanitaires multiples.

Coral Holobiont Omics: Microbes and Dinoflagellates: Principles and Applications

Chapter

Full-text available

Aug 2016

Human enteric viruses in groundwater indicate offshore transport of human sewage to coral reefs of the Upper Florida Keys

Article

Apr 2010

To address the issue of human sewage reaching corals along the main reef of the Florida Keys, samples were collected from surface water, ground-water and coral [surface mucopolysaccharide layers (SML)] along a 10 km transect near Key Largo, FL. Samples were collected semi-annually between July 2003 and September 2005 and processed for faecal indicator bacteria (faecal coliform bacteria, enterococci and Clostridium perfringens) and human-specific enteric viruses (enterovirus RNA and adenovirus DNA) by (RT)-nested polymerase chain reaction. Faecal indicator bacteria concentrations were generally higher nearshore and in the coral SML. Enteric viruses were evenly distributed across the transect stations. Adenoviruses were detected in 37 of 75 samples collected (49.3%) whereas enteroviruses were only found in 8 of 75 samples (10.7%). Both viruses were detected twice as frequently in coral compared with surface water or groundwater. Offshore, viruses were most likely to be found in groundwater, especially during the wet summer season. These data suggest that polluted groundwater may be moving to the outer reef environment in the Florida Keys.

Persistence of wastewater enteroviruses in Yopougon Ivory Coast

Article

Jan 2011

Several environmental factors contribute to maintain infectivity of enteroviruses out of body in various hydrological media, sometimes for long periods. This in situ study aimed (i) to isolate these viruses from wastewater and a lagoon, in four cell lines, and (ii) to follow the distribution and persistence of these viruses under the influence of abiotic environmental factors. The wastewater samples were collected at nine sampling points along the channel, which flows into a tropical lagoon in Yopougon. Enteroviruses were concentrated by using Dextran T40 and polyethylen glycol 6000, according to WHO recommendations. Measurements of pH, temperature, conductivity and salinity were carried out on site. The determination of sulphates (SO4 2-) was performed by HACH method 8051. Among the samples of raw wastewater (n = 45) and lagoon water (n = 21), 68.9% and 52.4%, respectively, were positive for viral isolation. The presence of enteroviruses was confirmed by RT-PCR in 57.8% and 42.8% of samples of raw wastewater and lagoon water. We observed that for rainfall of 0.4 mm and 252.9 mm, the number of positive samples collected was respectively 44.4% and 60.9%. Moreover, infectious enteroviruses were detected in the lagoon environment for temperatures ranging from 26oC to 30oC, above the threshold of 22oC where survival would be affected in estuaries. This study seems to demonstrate that the maximum value of pH (pH Max = 9.57) and salinity (salinity Max = 10.7) coupled with other environmental factors do not allow the persistence of enteroviruses.

Recovery rate of multiple enteric viruses artificially seeded in water and concentrated by adsorption-elution with negatively charged membranes: Interaction and interference between different virus species

Article

Dec 2015
WATER SCI TECHNOL

Viral concentration method by adsorption-elution with negative membranes has been widely employed for concentrating viruses from environmental samples. In order to provide an adequate assessment of its recovery efficiency, this study was conducted to assess viral recovery rates for viral species commonly found in water (HAdV-5, EV, RV, BAdV and CAV-2), quantifying viral genomes at the end of the five different steps of the process. Recovery rates were analyzed for several viruses combined in a single water sample and for each virus assayed separately. Ultrapure water samples were artificially contaminated and analyzed by real-time quantitative polymerase chain reaction (qPCR). High recovery rates were found after the final stage when assessed individually (89 to 125%) and combined in the same sample (23 to > 164%). HAdV-5 exhibited >100% recovery when assayed with human viruses and other AdVs, whereas BAdV and CAV-2 were not detected. These data suggest that recovery efficiency could be related to viral structural characteristics, their electric charges and other interactions, so that they are retained with greater or lesser efficiency when coupled. This protocol could be applied to environmental samples, since high recovery rates were observed and infectious viruses were detected at the end of the concentration process.

Shellfish and Microbial Source Tracking

Chapter

Jan 2007

Pathogen Measurements in the St. Lucie River Estuary

Article

Full-text available

Microbes At A Non-Point Source Sub-Tropical Recreational Marine Beach And Their Implications On Human Health And Beach Monitoring Practices

Article

DEVELOPMENT OF A NEW MICROPOROUS FILTER METHOD FOR THE CONCENTRATION OF VIRUSES FROM WATER

Article

Luisa A Ikner

Molecular Methods in Food Safety Microbiology: Interpretation and Implications of Nucleic Acid Detection

Article

Full-text available

Jul 2014
COMPR REV FOOD SCI F

Because of increasing demand for rapid results, molecular techniques are now applied for the detection of microorganisms in foodstuffs. However, interpretation problems can arise for the results generated by molecular methods in relation to the associated public health risk. Discrepancies between results obtained by molecular and conventional culture methods stem from the difference in target, namely nucleic acids instead of actively growing microorganisms. Nucleic acids constitute 5% to 15% of the dry weight of all living cells and are relatively stable, even after cell death, so they may be present in a food matrix after the foodborne microorganisms have been inactivated. Therefore, interpretation of the public health significance of positive results generated by nucleic acid detection methods warrants some additional consideration. This review discusses the stability of nucleic acids in general and highlights the persistence of microbial nucleic acids after diverse food-processing techniques based on data from the scientific literature. Considerable amounts of DNA and RNA (intact or fragmented) persist after inactivation of bacteria and viruses by most of the commonly applied treatments in the food industry. An overview of the existing adaptations for molecular assays to cope with these problems is provided, including large fragment amplification, flotation, (enzymatic) pretreatment, and various binding assays. Finally, the negligible risks of ingesting free microbial nucleic acids are discussed and this review ends with the future perspectives of molecular methods such as next-generation sequencing in diagnostic and source attribution food microbiology.

Direct typing of human enteroviruses from wastewater samples

Article

Jul 2014
J VIROL METHODS

A RT-PCR approach for the direct detection and typing of human enteroviruses in the environment is described in this study. A semi-nested RT-PCR using COnsensus-DEgenerated Hybrid Oligonucleotide Primers (CODEHOP) designed from the VP2 genome region has been developed for the direct typing of enteroviruses in clinical samples (Ibrahim et al., 2013). This CODEHOP/VP2 PCR strategy as well as the CODEHOP/VP1 technique described by Nix et al. in 2006, were tested for the detection and typing of enteroviruses in 172 wastewater samples. Virus particles were first extracted and concentrated from wastewater samples by using respectively beef extract and polyethylene glycol 6000, and the presence of enteroviruses was screened by a RT-PCR method using primers from the 5'-end non coding region (5'NCR). Fifty-two of 172 samples (30.2%) were revealed positive by the 5'NCR method. From these 52 samples, only 19 samples (36.5%) were found positive by at least one of the two CODEHOP techniques, with the following distribution: VP1(+)/VP2(+)=4 (7,7%), VP1(-)/VP2(+)=13 (25%) and VP1(+)/VP2(-)=2 (3.8%). These results illustrate that the direct typing of enteroviruses in environmental samples is insensitive, possibly due to the presence of large amounts of amplification inhibitors; however, the VP2 method was found able to allow the direct detection and typing of c. one third of the positive environmental samples.

Marine Recreation and Public Health Microbiology: Quest for the Ideal Indicator

Article

Full-text available

Jan 2001
BIOSCIENCE

Rapid Movement of Wastewater from On-Site Disposal Systems into Surface Waters in the Lower Florida Keys

Article

Full-text available

Oct 2000

Viral tracer studies have been used previously to study the potential for wastewater contamination of surface marine waters in the Upper and Middle Florida Keys. Two bacteriophages, the marine bacteriophage ϕHSIC and theSalmonella phage PRD1, were used as tracers in injection well and septic tank studies in Saddlebunch Keys of the Lower Florida Keys and in septic tank studies in Boot Key Harbor, Marathon, of the Middle Keys. In Boot Key Harbor, both phages were detected in a canal adjacent to the seeded septic tank within 3 h 15 min of the end of the seed period. The tracer was then detected at all sampling sites in Boot Key Harbor, including one on the opposite side of U.S. Highway 1 in Florida Bay, and at an Atlantic Ocean beach outside Boot Key Harbor. Rates of migration based on first appearance of the phage ranged from 1.7 to 57.5 m h−1. In Saddlebunch Keys, ϕHSIC and PRD1 were used to seed a residential septic tank and a commercial injection well. The septic tank tracer was not found in any surface water samples. The injection well tracer was first detected at a site most distant from the seed site, a channel that connected Sugarloaf Sound with the Atlantic Ocean. The, rate of tracer migration from the injection well to this channel ranged from 66.8 to 141 m h−1. Both tracer studies showed a rapid movement of wastewater from on-site sewage treatment and disposal systems in a southeasterly direction toward the reef tract and Atlantic Ocean, with preferential movement through tidal channels. These studies indicate that wastewater disposal systems currently in widespread use in the Florida Keys can rapidly contaminate the marine environment.

Human Adenoviruses and Coliphages in Urban Runoff-Impacted Coastal Waters of Southern California

Article

Full-text available

Feb 2001

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.

Failure of indicator bacteria to reflect the occurrence of enteroviruses in marine waters

Article

Full-text available

Dec 1979

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.

Occurrence of Fecal Indicator Bacteria in Surface Waters and the Subsurface Aquifer in Key Largo, Florida

Article

Full-text available

Jun 1995

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)

Analysis of viral RNA persistence in seawater by reverse transcriptase- PCR

Article

Full-text available

Feb 1995

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.

Detection of Viral Pathogens by Reverse Transcriptase PCR and of Microbial Indicators by Standard Methods in the Canals of the Florida Keys

Article

Full-text available

Sep 1999

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli, Clostridium perfringens, enterococci, coliphages, F-specific (F(+)) RNA coliphages, Giardia lamblia, Cryptosporidium parvum, and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1, 410, E. coli organisms from <1 to 130, Clostridium spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F(+) phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.

Preliminary evidence for human fecal contamination in corals of the Florida Keys, USA

Article

Full-text available

Jul 2002
MAR POLLUT BULL

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.

Mechanisms and Rates of Decay of Marine Viruses in Seawater

Article

Full-text available

Dec 1992

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

Viral Tracer Studies Indicate Contamination of Marine Waters by Sewage Disposal Practices in Key Largo, Florida

Article

Full-text available

Jul 1995

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.

Virus Decay and Its Causes in Coastal Waters

Article

Full-text available

Feb 1997

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.

Comparison of Poliovirus Detection in Water by Cell Culture and Nucleic Acid Hybridization

Article

Feb 1993
WATER SCI TECHNOL

The nucleic acid hybridization technique has been used to detect viral nucleic acid in environmental water samples. 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° C and 15° C for 75 days, and in dechlorinated tapwater 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 samples, a parallel decline in virus detectable by gene probe occurred in all other water samples.

Detection of Viral Pathogens by Reverse Transcriptase PCR and of Microbial Indicators by Standard Methods in the Canals of the Florida Keys

Article

Feb 2000

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli , Clostridium perfringens , enterococci, coliphages, F-specific (F ⁺ ) RNA coliphages, Giardia lamblia , Cryptosporidium parvum , and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1,410, E. coli organisms from <1 to 130, Clostridium spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F ⁺ phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.

Detection of enteroviruses and hepatitis A virus in environmental samples by gene probes and polymerase chain reaction

Article

Jan 1990

Laboratory methods for the growth and detection of animal viruses

Article

Jan 1982

An Introduction to Environmental Archaeology

Article

Dec 1981

Human Adenoviruses and Coliphages in Urban Runoff-Impacted Coastal Waters of Southern California

Article

Jan 2001
J APPL MICROBIOL

Human Enteric Viruses and Parasites in the Marine Environment

Article

Dec 2001
Meth Microbiol

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.

Breakdown and microbial uptake of marine viruses and other lysis products

Article

Nov 1999

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.

Introduction to Environmental Virology

Article

Oct 1981

Wylie D. Burge

Influence of environmental factors on the survival of enteric viruses in seawater

Article

Nov 1998
Oceanol Acta

Aggregation as a factor in loss of viral titer in seawater

Article

May 1975
WATER RES

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.

Enteroviruses detected by reverse transcriptase polymerase chain reaction from the coastal waters of Santa Monica Bay, California: Low correlation to bacterial indicator levels

Article

Jan 2001

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.

The Effects of Seasonal Variability and Weather on Microbial Fecal Pollution and Enteric Pathogens in a Subtropical Estuary

Article

Jan 2001

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.

Evidence for groundwater and surface marine water contamination by waste disposal wells in the Florida Keys

Article

Jun 1997
WATER RES

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.

Poliovirus detection in water by cell culture and nucleic acid hybridization

Article

Jul 1993
WATER RES

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.

Comparative study of the behaviour of poliovirus in sterile seawater using RT-PCR and cell culture

Article

Dec 1994
MAR POLLUT BULL

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.

Hepatitis a virus and poliovirus 1 inactivation in estuarine water

Article

Nov 1987
WATER RES

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.

Devenir des virus enteriques en mer et influence des facteurs environmentaux

Article

Nov 1998
Oceanol Acta

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.

Concentration of enteroviruses from large volumes of tap water, treated sewage, and seawater

Article

Apr 1978

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.

Membrane filter enumeration method for Clostridium perfringens

Article

Feb 1979

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.

Stability of viruses in waste water sludge eluates

Article

Sep 1986

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).

Assessment and Impact of Microbial Fecal Pollution and Human Enteric Pathogens in a Coastal Community

Article

Apr 2001
MAR POLLUT BULL

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.

Comparative survival of enteric viruses and bacteria in Atlantic Ocean seawater

Article

Feb 2001
WATER SCI TECHNOL

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.

Detection, quantitation and identification of enteroviruses from surface waters and sponge tissue from the Florida Keys using real-time RT-PCR

Article

Jun 2002
WATER RES

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.

Comparative survival of Cryptosporidium, coxsackievirus A9 and Escherichia coli in stream, brackish and sea waters

Article

Feb 2003
WATER SCI TECHNOL

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.

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

Abstract

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