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.
[1] 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.