Somatic coliphage families as potential indicators of enteric viruses in water and methods for their detection

The potential use of specific somatic coliphage taxonomic groups as viral indicators on the basis of their persistence and prevalence in water was investigated. Representative type strains of the 4 major somatic coliphage taxonomic groups were seeded into environmental water and their survival was measured at temperatures of 23-25 and 4oC. Based on their greater persistence over time, the Myoviridae (type strain T4), the Microviridae (type strain PhiX174), and the Siphoviridae (type strain Lambda) were the preferred candidate somatic coliphages as candidate fecal indicator viruses in water. Also, a conventional, group-specific PCR method was developed to identify each of the 4 major taxonomic groups of somatic coliphages and used to classify individual somatic coliphage isolates from primary human sewage effluent to further document those detected and to describe their behavior in environmental waters. Over time, the taxonomic makeup of the somatic coliphage population in sewage changes, with the Microviridae family becoming the most prevalent taxonomic group in the sewage population after several weeks. Based on their persistence and prevalence in environmental waters, phages belonging to the Microviridae family could serve as indicators for sewage contamination and perhaps human enteric viruses in water. Rapid detection methods for reliable viral indicators that predict viral contamination in water are essential for timely protection of public health. Individual somatic coliphage families that are relatively persistent and abundant in environmental waters are possible reliable viral indicators. Rapid detection of the Microviridae family of somatic coliphages by real-time PCR method was developed and successfully applied to environmental water samples: primary sewage effluent of two different geographic regions, seawater, and groundwater. Also, as an antibody-based rapid detection method, CLAT (Culture, Latex Agglutination, and Typing), for the Siphoviridae family, N4-type viruses of the Podoviridae family, and T4-type viruses of Myoviridae, was developed and successfully applied to somatic coliphage isolates, although there is a need for improvement in method sensitivity and specificity. Developing new and rapid nucleic-based detection and antibody-based somatic coliphage detection and characterization methods will assist in future studies to evaluate individual somatic coliphage families as sewage and viral indicators for water quality assessment