Challenges and Opportunities in the Hydrologic Sciences

This is the Table of Contents and Introduction of a Report published as Hornberger, G. M., E. Bernhardt, W. E. Dietrich, D. Entekhabi, G. E. Fogg, E. Foufoula-Georgiou, W. J. Gutowski, W. B. Lyons, K. W. Potter, S. W. Tyler, H. J. Vaux, C. J. Vorosmarty, C. Welty, C. A. Woodhouse, C. Zheng, Challenges and Opportunities in the Hydrologic Sciences. 2012: Water Science and Technology Board, Division on Earth and Life Studies, National Academy of Sciences, Washington, DC. 173 pp. Posted with permission.</p

Virus persistence in ground water

Ground water has traditionally been considered safe for human consumption without treatment. However, it is an increasingly significant cause of human disease. Although ground water accounts for only approximately 20% of the nation's water supply, over 50% of the waterborne disease outbreaks in the United States are due to the consumption of contaminated ground water. It has been estimated that 65% of the cases of illness in these outbreaks are caused by enteric viruses. Little, however, is known about the persistence of viruses in ground water. The purpose of this study was to try to determine the chemical, physical, and biological factors influencing virus survival in ground water. This information will be helpful in developing criteria for determining safe distances between drinking water wells and sources of potential contamination such as septic tanks and waste application sites. Ground water samples were obtained from eleven sites throughout the United States. In addition, twenty samples were collected from the Tucson basin. The water temperature was measured at the time of collection. Several physical and chemical characteristics (including pH, nitrates, turbidity, and hardness) were determined for each sample. Separate polypropylene tubes containing 50 ml of water were inoculated with each of three viruses: poliovirus-1, echovirus-1 and MS-2 coliphage. Duplicate tubes containing water which had been filtered to remove the indigenous bacteria were also inoculated with viruses. The tubes were incubated at the in situ ground water temperature; selected samples were incubated at two additional temperatures. One-ml subsamples were withdrawn at predetermined intervals over a 30-day period and assayed to determine the number of microorganisms remaining. Multiple regression analysis revealed that temperature was the only water characteristic significantly correlated with the decay rates of all three viruses. Bacteria did not have a consistent effect on the decay rate of the viruses. In addition, no significant differences were found among the decay rates of the three viruses, suggesting that MS-2 coliphage may be able to be used as a model of animal virus behavior in the environment.hydrology collectio

Development of a rapid, sensitive, and quantitative method to detect infective hepatitis, a virus in water

Microorganisms are responsible for more than 90% of the reported waterborne disease outbreaks in the United States; enteric viruses, such as hepatitis A virus, are identified as causing almost 10% of these. However, in 50% of the outbreaks, no causative agent is identified due to limitations in our ability to isolate and detect viruses in water samples. Historically, consumption of contaminated ground water has been the source of one-half of the reported outbreaks; in recent years, that fraction has risen to more than two-thirds. The most frequently reported source of contamination in these outbreaks is domestic sewage from septic tanks, leaking sewer lines, cesspools, etc.As a result of the continuing waterborne disease outbreaks, and the growing fraction of them associated with consumption of ground water, the USEPA is finalizing a regulation, the Ground Water Rule, to minimize the risk of acquiring a microbial illness from ground water. This regulation will require all public water systems that use ground water as a source to assess the potential for fecal contamination of the water. One potential source of fecal contamination is the reuse of recycled water. Even tertiary treated wastewater may contain contaminants, including disease-causing microorganisms such as viruses, bacteria and parasites. Information about the numbers and types of some of these microorganisms, especially viruses, present in tertiary treated wastewater is scarce due to the limitations in the methods that are needed to detect these microorganisms in water. Current methods to detect viruses in water samples, for example, require highly specialized analytical facilities and at least two to four weeks to obtain results. In addition, the standard methods only detect one group of viruses, the enteroviruses (which includes polioviruses). From records on waterborne disease outbreaks in the U.S., it is known that the enteroviruses are not the major cause of reported viral waterborne disease; other viruses such as hepatitis A virus and caliciviruses are the public health concern. The lack of information about the presence of hepatitis A virus in water and its long survival times in water caused the USEPA to add it to the list of contaminants to be considered for regulation in drinking water.When recycled water is used to artificially recharge groundwater, there is the potential for some microorganisms, especially viruses due to their small size, to contaminate the underlying groundwater. Although most of the microorganisms may be removed during recharge, if even a few are transported to the ground water, that is of concern, as the USEPA has determined that one virus in 10,000 liters of drinking water constitutes a public health concern.Molecular beacons (MB) are oligonucleotide probes that become fluorescent upon hybridization and are ideal in providing real-time monitoring of target amplicons during the PCR reaction. In this project, a real-time PCR assay based on molecular beacons was developed for the rapid and specific detection of hepatitis A virus. Using the MB-based RT-PCR assay, a detection limit of 1 PFU per PCR reaction was obtained. The specificity of the MB-based PCR assay was evaluated using a variety of other enteric organisms, and only hepatitis A virus was positively identified. The method developed in this study should improve our ability to provide rapid, sensitive, and specific results for the detection and quantitation of viruses in samples from environmental waters

Environmental Microbiology : the dictionary

iii, 178 p. : ill.; 22 cm

Detection of Infective Poliovirus by a Simple, Rapid, and Sensitive Flow Cytometry Method Based on Fluorescence Resonance Energy Transfer Technology▿

The rapid and effective detection of virus infection is critical for clinical management and prevention of disease spread during an outbreak. Several methods have been developed for this purpose, of which classical serological and viral nucleic acid detection are the most common. We describe an alternative approach that utilizes engineered cells expressing fluorescent proteins undergoing fluorescence resonance energy transfer (FRET) upon cleavage by the viral 2A protease (2Apro) as an indication of infection. Quantification of the infectious-virus titers was resolved by using flow cytometry, and utility was demonstrated for the detection of poliovirus 1 (PV1) infection. Engineered buffalo green monkey kidney (BGMK) cells expressing the cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) substrate linked by a cleavage recognition site for PV1 2Apro were infected with different titers of PV1. After incubation at various time points, cells were harvested, washed, and subjected to flow cytometry analysis. The number of infected cells was determined by counting the number of cells with an increased CFP-to-YFP ratio. As early as 5 h postinfection, a significant number of infected cells (3%) was detected by flow cytometry, and cells infected with only 1 PFU were detected after 12 h postinfection. When applied to an environmental water sample spiked with PV1, the flow cytometry-based assay provided a level of sensitivity similar to that of the plaque assay for detecting and quantifying infectious virus particles. This approach, therefore, is more rapid than plaque assays and can be used to detect other viruses that frequently do not form clear plaques on cell cultures

Salivary Detection of Dengue Virus NS1 Protein with a Label-Free Immunosensor for Early Dengue Diagnosis.

Dengue virus (DENV) is a highly pathogenic, arthropod-borne virus transmitted between people by Aedes mosquitoes. Despite efforts to prevent global spread, the potential for DENV epidemics is increasing world-wide. Annually, 3.6 billion people are at risk of infection. With no licensed vaccine, early diagnosis of dengue infection is critical for clinical management and patient survival. Detection of DENV non-structural protein 1 (NS1) is a clinically accepted biomarker for the early detection of DENV infection. Unfortunately, virtually all of the laboratory and commercial DENV NS1 diagnostic methods require a blood draw for sample analysis, limiting point-of-care diagnostics and decreases patient willingness. Alternatively, NS1 in human saliva has been identified for the potential early diagnosis of DENV infection. The collection of saliva is simple, non-invasive, painless, and inexpensive, even by minimally trained personnel. In this study, we present a label-free chemiresistive immunosensor for the detection of the DENV NS1 protein utilizing a network of single-walled carbon nanotubes functionalized with anti-dengue NS1 monoclonal antibodies. NS1 was successfully detected in adulterated artificial human saliva over the range of clinically relevant concentrations with high sensitivity and selectivity. It has potential application in clinical diagnosis and the ease of collection allows for self-testing, even within the home

Salivary Detection of Dengue Virus NS1 Protein with a Label-Free Immunosensor for Early Dengue Diagnosis

Dengue virus (DENV) is a highly pathogenic, arthropod-borne virus transmitted between people by Aedes mosquitoes. Despite efforts to prevent global spread, the potential for DENV epidemics is increasing world-wide. Annually, 3.6 billion people are at risk of infection. With no licensed vaccine, early diagnosis of dengue infection is critical for clinical management and patient survival. Detection of DENV non-structural protein 1 (NS1) is a clinically accepted biomarker for the early detection of DENV infection. Unfortunately, virtually all of the laboratory and commercial DENV NS1 diagnostic methods require a blood draw for sample analysis, limiting point-of-care diagnostics and decreases patient willingness. Alternatively, NS1 in human saliva has been identified for the potential early diagnosis of DENV infection. The collection of saliva is simple, non-invasive, painless, and inexpensive, even by minimally trained personnel. In this study, we present a label-free chemiresistive immunosensor for the detection of the DENV NS1 protein utilizing a network of single-walled carbon nanotubes functionalized with anti-dengue NS1 monoclonal antibodies. NS1 was successfully detected in adulterated artificial human saliva over the range of clinically relevant concentrations with high sensitivity and selectivity. It has potential application in clinical diagnosis and the ease of collection allows for self-testing, even within the home