AWWA WQTC57172

AWWA WQTC57172 Coliphages as Indicators of Viral Contamination in Water
Conference Proceeding by American Water Works Association, 11/01/2002

Meschke, John Scott; Sobsey, Mark D.; Stewart, Jill R.

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Human enteric viruses (such as the Hepatitis A virus, Rotaviruses, Adenoviruses, Astroviruses, and Caliciviruses, including noroviruses and sapoviruses) pose serious risks of waterborne disease. Many of these viruses have relatively low infectious doses, are fecally shed at high concentrations (often millions to billions per gram feces), are environmentally persistent and more resistant to common treatment practices than many bacteria, and can contaminate water from various sources of human fecal wastes. Detection and enumeration of human enteric viruses is neither practical nor cost-efficient for routine monitoring in water samples. As a consequence, surrogate microorganisms are commonly relied upon to indicate fecal contamination of water. However, human enteric viruses have been repeatedly isolated from waters with low or non-detectable concentrations of standard bacterial indicators, and outbreaks have been reported from drinking waters which have met standard indicator criteria. In response to the shortcomings of bacterial indicators, enteric bacteriophages, somatic and male-specific, have been proposed as indicators for human enteric viruses in fecally contaminated water. In addition to being indicators of fecal contamination, the male-specific coliphages have been suggested as index organisms for source-typing of fecal contamination. This paper summarizes the results of several recent studies on the suitability of coliphages, compared to bacteria, as indicators of human enteric viruses in water, and as index organisms for fecal source tracking. Characteristics of bacteriophages, and the taxonomy and physical characteristics of coliphages are discussed. Studies on the suitability of coliphages as indicators of human enteric viruses in water include: coliphage occurrence in the environment; persistence and mobility of coliphages; coliphage thermotolerance and host specificity; coliphage resistence to treatment processes; and, improved methods of coliphage detection. Includes 42 references.