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OCCURRENCE OF ENTERIC VIRUSES IN WATERS
Citation:
Fout, G S. OCCURRENCE OF ENTERIC VIRUSES IN WATERS. Presented at Safe Drinking Water Meeting, Saskatoon, Saskatchewan, Canada, May 4-12, 2001.
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:
A number of different types of human enteric viruses cause waterborne outbreaks when individuals are exposed to contaminated drinking and recreational waters. Vaccination against poliovirus has virtually eliminated poliomyelitis from the planet, but other members of the enterovirus group to which poliovirus belongs cause numerous diseases, including gastronenteritis, encephalitis, meningitis, myocarditis and perhaps diabetes and chronic fatigue syndrome. Because of these diseases and the uncertainty about their waterborne spread the coxsackie and echovirus members of the enterovirus group have been placed on EPA's Contaminant Candidate List. Hepatitis A and more recently hepatitis E have caused larged waterborne hepatitis outbreaks. The second leading cause of illness in the United States is acute nonbacterial gastroenteritis. This disease results from infection of susceptible individuals with members of the Caliciviridae, Astroviridae, Reoviridae and Adenoviridae families.
The first step in establishing the risk of waterborne disease from these viruses is to determine the levels of their occurrence in contaminated waters. Occurrence measurement requires methods to recover, identify and measure the concentration of viruses in affected waters. Viruses are recovered and concentrated from water by passage through a positively charged cartridge filter. Following virus elution from the cartridge filter with beef extract and concentration of the beef extract solution, viruses are usually assayed by cell culture. However, cultural methods are too time consuming and expensive for routine use and many of the viruses that cause waterborne disease are either very difficult to culture or cannot be cultured.
To overcome these problems, we developed a rapid multiplex polymerase chain reaction (PCR) method that can detect many of the virus groups known to cause waterborne disease. This method has been effectively used to measure virus levels in surface and drinking waters. The results of these studies will be discussed.