Coliphage
A coliphage is a type of bacteriophage that infects coliform bacteria such as Escherichia coli. Coliphage originate almost exclusively from human feces and from other warm-blooded animals. When certain circumstances are met, such as a large number of susceptible hosts present at the right temperature, they can only partially replicate in sewage and contaminated waters. Examples include Enterobacteria phage λ and species from the family Fersviridae. Coliphage levels reflect the persistence of pathogenic viruses in the environment and have been proposed as an indicator of fecal contamination in water. References

External links 
 
A science project targeted towards students showing an example of the use of Coliphages

Bacteriophages