Bacterial Indicators and Potential Health Hazard of Aquatic Viruses

A fundamental difference exists between bacterial (living) and viral (nonliving) organisms in that a virus is a parasite depending on living host cells for material and energy to replicate viral entities. Therefore, an “indicator organism” for virus hazards must take into account the fact that a virus must be able to travel among hosts in order to remain virulent. In this paper, the author modifies the usual connotation of indicator organism to include an “indicator system” which consists of virus and the host on which it is assayed. The state of the art on virus hazards is examined in the light of the advanced technology useful to engineers in the solution of virus problems in water reuse. It is generally accepted that a virus is the most suitable “indicator organism” for a virus. The research use of various virus indicators is here briefly reviewed and requirements for a timely and realistic indicator system is set forth. A system containing multiple hosts is suggested, and data are given as to its effectiveness in monitoring virus quality in reuse water, sludges, and soil.