Grantee Research Project Results
Norwalk Virus-Like Particles (VLPs) for Studying Natural Groundwater Disinfection
EPA Grant Number: R824775Title: Norwalk Virus-Like Particles (VLPs) for Studying Natural Groundwater Disinfection
Investigators: Grant, Stanley B. , Estes, Mary K.
Current Investigators: Grant, Stanley B. , Estes, Mary K. , Olson, Terese M. , Ogunseiten, Oladele
Institution: University of California - Irvine
Current Institution: University of California - Irvine , University of Michigan
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1995 through August 1, 1996 (Extended to October 31, 1999)
Project Amount: $230,000
RFA: Water and Watersheds (1995) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Description:
Many outbreaks of gastroenteritis occur in the U.S. and these are often caused by waterborne or foodborne transmission of Norwalk virus (NV). Some of these outbreaks can be traced to the contamination of groundwater supplies by inadequate filtration of sewage effluent from private or community septic tank systems. To limit the spread of microbial pathogens through groundwater, the U.S. EPA has proposed a new set of rules under the 1996 reauthorization of the Safe Drinking Water Act that would require public water systems to disinfect source water from each groundwater well unless "natural disinfection" can be demonstrated or a variance can be obtained. With respect to NV, however, the efficacy of these proposed rules is questionable because the environmental variables that control the "natural disinfection" of this particular viral pathogen in subsurface systems are largely unknown. We are utilizing recombinant Norwalk virus (rNV) particles as a model system to overcome the long-standing barrier to conducting filtration experiments with NV. These particles are produced by a molecular biology procedure in which the gene for the single structural protein for NV is cloned into a baculovirus expression system. When the recombinant capsid protein is expressed, it spontaneously self-assembles into virus-like particles (VLPs) that are morphologically and antigenically identical to the native Norwalk virus. The resulting rNV VLPs differ from live NV in only one known but important respect: they lack the genetic material (in particular, RNA) necessary for replication in the host. Thus, while the rNV VLPs "look" like a real Norwalk virus, they are harmless protein particles that cannot initiate infection in humans. The idea behind the current project is to utilize these rNV VLPs, which were originally developed for a new human vaccine, to investigate the natural removal of Norwalk virus in groundwater by physicochemical filtration.In the first year of this project, we have completed a set of experiments examining the influence of pore water pH on the surface charge of the rNV VLPs and their filtration rates in packed beds of quartz sand (manuscript submitted for publication). These initial results suggest that pore water pH may be the most important factor in determining the capacity of groundwater systems to provide "natural disinfection" by physicochemical filtration. Ultimately, the rNV VLPs could lead to new approaches for establishing set-back distances between groundwater wells and potential sources of viral pathogens (like groundwater recharge basins and septic tanks) and for assessing the degree to which water contaminated with human waste is "naturally disinfected" by percolation through the subsurface matrix.
Publications and Presentations:
Publications have been submitted on this project: View all 15 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 2 journal articles for this projectSupplemental Keywords:
water, drinking water, groundwater, human health, viruses, hydrology, biology., RFA, Scientific Discipline, Water, Water & Watershed, Hydrology, Environmental Chemistry, Chemistry, Drinking Water, Biology, Watersheds, pathogens, alternative disinfection methods, microbial contamination, public water systems, groundwater disinfection, contaminant transport, human health effects, microbiological organisms, Norwalk, waterborne disease, NLVs, viruses, natural disinfection, microbial pathogens, Norwalk Virus, gastroenteritis, microbial pollution, microbial risk management, aquatic ecosystems, filtration of sewage effluent, drinking water contaminants, groundwaterProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.