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METHODS USED TO ANALYZE A NOROVIRUS OUTBREAK
Citation:
Cashdollar, J L., S. Parshionikar, C Newport, S. WillianTrue, D R. Dahling, AND G S. Fout. METHODS USED TO ANALYZE A NOROVIRUS OUTBREAK. Presented at USEPA's Research on Micoorganisms in Drinking Water, Cincinnati, OH, August 5-7, 2003.
Impact/Purpose:
Overarching Objectives and Links to Multi-Year Planning
This task directly supports the Drinking Water Research Program Multi-Year Plan's long term goal to "develop scientifically sound data and approaches to characterize and manage risks to human health posed by exposure to waterborne pathogens and chemicals" under GRPA Goal 2 (Clean and Safe Water). The overarching objective is to provide the Office of Water, Agency risk assessors and managers, academics, the scientific community, state regulators, water industry and industry spokes groups with exploratory occurrence and exposure data on human enteric viruses. These data will improve the quality of risk-based assessments and tools used by the Agency to set regulations, policies and priorities for protecting human health and allow the Agency to assure the public that the appropriate methods are being used to demonstrate that drinking water is safe from pathogenic agents.
Specific Subtask Objectives:
o Conduct an exploratory occurrence studies on emerging human waterborne pathogenic viruses and viruses on the Contaminant Candidate List (CCL) in water (Subtask A; to be completed by 9/05 in support of LTG 1 (due 2010)).
o Determine the relationship of bacterial virus indicators to human enteric virus occurrence in the above studies (Subtask A; to be completed by 9/05 in support of LTG 1 (due 2010)).
o Develop a non-invasive assay for measuring human exposure to viruses (Subtask B; to be completed by 9/05 in support of LTG 1 (due 2010)).
Description:
Project Goals and Objectives:
To isolate and identify the viral agents in well water samples associated with two outbreaks of acute gastroenteritis reported to the Wyoming Department of Health in February 2001 and October 2001. To isolate and identify the viral agents in patient stool samples and to determine the link between water consumption and illness.
Approach:
The project had a three way approach:
An epidemiological investigation was performed to identify any common routes of exposure among those afflicted with gastroenteritis.
An environmental survey was done of the premises involved in each outbreak to determine possible sources of contamination.
Laboratory analysis was performed on well water samples for coliform and viral detection using RT-PCR and DNA sequencing. Stool samples were also analyzed for the presence of noroviruses.
Preliminary Findings:
Epidemiological studies revealed a close association between water consumption and illness. Environmental surveys in both outbreaks determined that the water supply was vulnerable to fecal contamination. Well water samples in both cases were positive for coliforms, and RT-PCR and DNA sequencing revealed noroviruses as the causative agents of acute gastroenteritis.
Significance of Findings:
This investigation demonstrates that EPA's viral concentration and molecular methods in conjunction with epidemiological and environmental analysis are very useful in outbreak studies.
Next Steps:
The methods used in this study can be performed in most laboratories with trained personnel and appropriate equipment, which would allow for routine monitoring of enteric viruses in drinking water, thus preventing any future outbreaks from occurring.